Note: Descriptions are shown in the official language in which they were submitted.
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FEIILING W~DGE
Background of Invention
This invention relates to a wedge used in conjunction with
a chain saw for felling or bucking trees.
In the process of cutting down a large tree (felling) or
cutting the fallen tree into designated lengths (bucking) it
is not unco~mon for the kerf that is being cut by the saw to
slightly collapse during cutting. When this occurs, the cutting
portion of the saw that is in the kerf is pinched between the
sections of the tree. Getting the pinched saw out of the kerf
can be difficult ana the cutting chain and guide bar of the
saw can be damaged.
A solution to the pinched saw problem is the felling wedge.
When the depth of cut exceeds the width of the chain and bar,
the point of the felling wedge is inserted into the kerf be-
hind the chain and bar. As cutting continues, the wedge is
pexiodically driven into the kerf to prevent collapsing. The
wedge in fact will spread the kerf to insure free cutting.
An alternate use of the felling wedge is to control the
direction of fall of the tree. Techniques are used to direct
the fall of the tree but on occasion, such techniques are not
sufficient, e.g., when a tree is leaning away from the direc-
tion where felling is desired. In such instances the wedge
will assist in "lifting'1 the tree in the direction desired.
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Because considerable forces are exerted on the wedge, the
material from which it is made is required to be tough. How-
ever, this material must also be of a consistency that allows
it to be easily cut by the cutting chain. It is quite common
for the cutting chain of the chain saw to contact the wedge
during the cutting operation. The cutting edges of the saw
chain are specifically designed to cut wood and even the
slightest contact with a hard material such as metal will
instantly dull the cutting edges of the entire chain. It
is far better to slightly damage the wedge than to dull the
saw chain.
It is very common to produce the wedges out of molded
plastic. A suitable plastic wedge is described in the U.S.
Patent #3185442. Such plastic is tough enough to be wedged
into a kerf of a large tree, but is easily cut by a saw
chain cutter without significant dulling~ The problem with
the plastic wedg~ is that it is quite easily damaged by the
pounding of a driving mall. The stxiking force of the mall
against the butt end of the wedge will cause splaying of the
end and creates a rim of the material that projects outwardly
from the side of the wedge. Whereas it is often desirable
to drive the wedge as far into the cut as possible, when the
rim is formed at the butt end it functions to limit the
penetration, i.e., when the rim is brought flush up against
the tree. A further problem is created by miss hits of the
driving mall. In the same manner that the wedge can be cut
by the cutting chain, when an axe or mall does not hit the
butt end squarely, i.e., when it catches a corner of the
wedge, the wedge is chipped and repea~ed miss hits quickly
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damages the wedge beyond use. The conditions just described
insures a short life for the wedge.
Summary of Invention
The invention provides a felling wedge for use in
conjunction with a cutting saw in felling and bucking trees,
comprising: a main body portion having a narrow end and a bu-tt
end and sides that diverge from the narrow end to the butt end,
and a cap having a luy depending therefrom, said lug being
embedded in the main body portion at the butt end thereof to
secure the cap to the butt end oE the main body portion, said
main body portion constructed of a material softer than the
material of the cap whereby the main body portion is relatively
more compatible to being cut by the chain saw and the cap is
relatively more compatible to being struck by a driving mall.
In the preferred embodiment, the cap is of hard metal
and a pair of metal studs depend from one side of the cap and
these studs are projected into the plastic of the main body
portion of the wedge. Holes are provided in the studs and the
plastic in molten form, e.g., when being cast, flows around the
studs and through the holes to tightly secure the metal cap to the
plastic. A further preferred modifica~ion is the provision of a
head portion that encompasses the me-tal cap. The sides of the
head portion are inset from the flared sides of the main body
portion. As the head portion is driven into the kerf, the metal
cap will thus easily pass into the kerf opening.
Detailed Description Including Drawings
Having thus briefly described the preferred embodiment
of the invention, a more detailed description of the invention is
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provided hereafter, including drawings wherein:
Figure 1 is a view of a felling wedge, of the present
invention, being driven into the kerf of a tree being felled;
Figure 2 is an enlarged view of the felling wedge with
a portion cross sectioned to illustrate the interconnection of
the two components of the wedge;
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Fig. 3 is a perspective view vf the cap of the wedge
with the main body porti~n sh~wn in dashed lines; and
Fig. 4 is a ~iew of the felling wedge driven all ~he
way into the kerf of a tree.
Referring to Fig. l of the drawings, a tree 10 is
being felled in a conventional manner. A notch 12 has
been formed in the side of the tree to establish the
direction in which the tree is to be felled ~illustrated
by arrow 14). A kerf 16 is being cut into the tree by a
chain saw 18 (only a cross-section of the guidebar 20 and
cutting chain 22 of the chain saw is shown).
In that the chain ~aw 18 has fully entered the kerf
16 ~ing formed in the tree lO, a felling wedge 21 of this
invention is being driven into the kerf 16 by a driving
mall 23. The felling wedge 21 is more clearly shown in Fig.2.
The main body portion 24 is produced from a suitable plastic
material as by molding. The material is tough whereby it
resists compression. The sides 26 and 28 are slightly
flared from the narrow end 30 and as the wedge is driven
into the kerf, a ~light spreading ~f the kerf is achieved.
Thi~ provides clearance for the chain saw and allows the
saw chain to run mor~ freely. The sides 26 and 28 are
also preferably of rough consistency for gripping the kerf
walls so that the wedge will not pop back out of the kerf.
Referring again to Fig. 1, a typical situation is
shown i.e., where the wedge is driven into a closely ad-
jacent position relati~e to the cutting chain 22 of a chain
saw. It will be appreciated that angular adjustment of the
saw or simply backing the saw up for any one of a number of
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reasons will cause the ~ast running saw chain to contact the
wedge. The chain runs at such a high speed that in an instant,
all the cutters of the chain will have taken a "bite" out of
the wedge. A properly sharpened saw chain is very important
and considerable time and effort goes into maintaining the
chain. An abrasive or hard material, like metal, when con-
tacted by the chain will instantly dull the cutters to where
it will cut only at a fraction of its prior efficiency.
Relative to the cutting efficiency of the chain, wear life
of the wedge is a constant concern to the logger. Thus,
care is taken to insure that the material of the wedge has
a minimal effect on the saw chain when it is inadvertently
brought into contact with the wedge.
Fig. 1 also illustrates the severe pounding that is
imposed on the butt end 32 of the wedge. It will be appre-
ciated that driving the wedge 21 into the kerf requires a
great amount of force. This is typically achieved by strik-
ing the butt end 32 of the wedge with the heavy mall 23 as
illustrated by directional arrow 34. The plastic material
of the main body portion of the wedge 24, as compromi~ed to
minimize damage to the cutting chain, does not stand up well
to such pounding. A cap 36 is thus provided to receive the
striking force of the mall 23.
Re~erring to Figs. 2 and 3, the cap 36 is constructed
of hard metal material, e.g., hardened steel. A suitable
thickness is for example ~ inch. The planar dimension is
in accordance with the base dimensions of the main body
portion, e.g., 1~ inch by 3~ inch. A pair of lugs 38,
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integral with the cap 36, extend from the inner or under
side of the cap and are embedded in the plastic of the main
body portion 24. Preferably such embedding is accom-
plished at the time the main body portion 24 is molded.
Thus the lugs 38 are inserted into the molten plastic
and the plastic flows around the lugs and into the open-
ings 40. When the plastic sets, the cap is securely held
to the main body portion and the only way it will get re-
moved is by tearing a section of the plastic loose. An
alternative method of securing the cap to the plastic is
to provide a threaded bolt shank in place of the lugs
shown in Figs~ 2 an~ 3. Holes are drilled into the hard-
ened plastic just biy enough to accomodate the bolt shanks.
The bolt shanks are heated and then quickly placed into
the holes. The heat of the bolt melts the plastic, causing
it to flow between the threads. On cooling, the cap is
secured to the plastic.
Referring now to Fig. 4, it will be noted that sides
26 and 28 are slightly angles inwardly at the start of the
head portion. The significance of this in-setting of the
sides is that a clearance 43 is created between the head
portion 42 at its outer end and the kerf walls (that is
when the wedge is buried into the kerf as shown). Thus
a rim 44 which may be created by the extreme pounding of
the mall against the hard metal cap 36 will slip past the
kerf walls to the extent that the rim 44 does not exceed
the clearance 43.
The above described invention is believed to provide
a significant improvement in felling wedges. The utility
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of the wedge is greatly improved and the life is extended
far beyond that of conventional wedges. Furthermore, it
is believed that the wedge i5 more easily driven by reason
of the solid impact achieved by the driving mall striking
the solid metal cap rather than the softer material of the
plastic body portion. Others skilled in the art, upon
acquiring the information of this disclosure, will be able
to modify and perhaps improve on the invention. It is to
be understood, however, that such modifications are en-
compassed within the invention as specifically defined
and set forth in the appended claims.
