U.S. patent number 3,813,776 [Application Number 05/360,561] was granted by the patent office on 1974-06-04 for vibration isolation system particularly adapted for use with a chain saw.
This patent grant is currently assigned to McCullough Corporation. Invention is credited to Robert Eugene Frederickson, Walter Joseph Hammond.
United States Patent |
3,813,776 |
Frederickson , et
al. |
June 4, 1974 |
VIBRATION ISOLATION SYSTEM PARTICULARLY ADAPTED FOR USE WITH A
CHAIN SAW
Abstract
An improved vibration isolation system particularly adapted for
use with a chain saw and characterized by a diaphragm, journaled on
shaft means, and engaged on either side by resilient impedance
means. The shaft means may be connected with a vibrating assembly
which includes a chain saw engine and cutter chain, while the
diaphragm means may be connected with a support means within which
the vibrating assembly is resiliently supported.
Inventors: |
Frederickson; Robert Eugene
(South Gate, CA), Hammond; Walter Joseph (Lakewood, CA) |
Assignee: |
McCullough Corporation (Los
Angeles, CA)
|
Family
ID: |
23418527 |
Appl.
No.: |
05/360,561 |
Filed: |
May 15, 1973 |
Current U.S.
Class: |
30/381;
173/162.1; 248/659 |
Current CPC
Class: |
B27B
17/0033 (20130101); F16F 1/424 (20130101); F16F
2236/022 (20130101) |
Current International
Class: |
B27B
17/00 (20060101); F16F 1/42 (20060101); B27b
017/02 (); F16f 007/12 () |
Field of
Search: |
;30/123.4,381-389
;173/162 ;248/15,18,22,24,358R ;267/141,137 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Smith; Al Lawrence
Assistant Examiner: Ramsey; K. J.
Attorney, Agent or Firm: Burns, Doane, Swecker &
Mathis
Claims
What is claimed is:
1. In a chain saw having
a vibrating assembly including
an engine having a crankshaft and
cutter chain means traversing a cutting path;
support means including
handle means; and
a plurality of vibration isolation means interconnecting said
vibrating assembly and said support means;
the improvement comprising:
at least one of said vibration isolation means including
resilient diaphragm means having an aperture and extending
transversely of said cutting path;
shaft means passing through said aperture of said diaphragm means,
with said diaphragm means being journaled upon said shaft
means;
first, resilient, impedance means, mounted on said shaft means, and
abuttingly and separably engaging one side of said diaphragm
means;
second, resilient, impedance means, mounted on said shaft means,
and abuttingly and separably engaging an opposite side of said
diaphragm means;
first mounting means connecting said diaphragm means with one of
said vibrating assembly and said support means; and
second mounting means connecting said shaft means with the other of
said vibrating assembly and said support means.
2. In a chain saw having
a vibrating assembly including
an engine having a crankshaft and
cutter chain means traversing a cutting path;
support means including
handle means; and
a plurality of vibration isolation means interconnecting said
vibrating assembly and said support means;
the improvement comprising:
at least one of said vibration isolation means including
resilient diaphragm means having an aperture, extending
transversely of said cutting path, and extending generally parallel
with the axis of rotation of said crankshaft;
shaft means passing through said aperture of said diaphragm means,
with said diaphragm means being journaled upon said shaft
means;
first, resilient, impedance means, mounted on said shaft means, and
abuttingly and separably engaging one side of said diaphragm
means;
second, resilient, impedance means, mounted on said shaft means,
and abuttingly and separably engaging an opposite side of said
diaphragm means;
first mounting means connecting said diaphragm means with one of
said vibrating assembly and said support means; and
second mounting means connecting said shaft means with the other of
said vibrating assembly and said support means.
3. A chain saw as described in claim 2:
wherein said diaphragm means includes a mounting wall portion
surrounding said aperture; and
wherein said first and second resilient impedance means define a
generally annular recess within which said mounting wall portion is
radially slidably and rotatably received.
4. A chain saw as described in claim 3:
wherein said mounting wall portion has flat parallel sides
surrounding said aperture of said diaphragm means; and
wherein said generally annular recess has flat parallel annular
wall portions continguous with said flat parallel sides of said
mounting wall portion.
5. A chain saw as described in claim 3:
wherein said mounting wall portion has a convex, generally annular
terminis surrounding said aperture of said diaphragm means; and
wherein said generally annular recess has a generally concave,
outwardly facing base, facing and engaging said generally convex
terminis.
6. A chain saw as described in claim 3 where each of said plurality
of vibration isolation means includes:
resilient diaphragm means having an aperture and extending
transversely of said cutting path;
shaft means passing through said aperture of said diaphragm means,
with said diaphragm means being journaled upon said shaft
means;
first, resilient, impedance means, mounted on said shaft means, and
abuttingly and separably engaging one side of said diaphragm
means;
second, resilient, impedance means, mounted on said shaft means,
and abuttingly and separably engaging an opposite side of said
diaphragm means;
first mounting means connecting said diaphragm means with one of
said vibrating assembly and said support means; and
second mounting means connecting said shaft means with the other of
said vibrating assembly and said support means.
7. A vibration isolating unit comprising:
resilient diaphragm means having an aperture;
shaft means passing through said aperture of said diaphragm means,
with said diaphragm means being journaled upon said shaft
means;
first, resilient, impedance means, mounted on said shaft means, and
abuttingly and separably engaging one side of said diaphragm means;
and
second, resilient, impedance means, mounted on said shaft means,
and abuttingly and separably engaging an opposite side of said
diaphragm means.
Description
BACKGROUND, OBJECTS, AND SUMMARY OF INVENTION
This invention constitutes an improvement in relation to a
vibration isolation system, particularly adapted for use with
internal combustion engine operated chain saws, and described in
U.S. Frederickson Pat. No. 3,542,095, U.S. Frederickson et al. Pat.
No. 3,652,074, and U.S. Frederickson et al. Pat. No. 3,698,455.
Each of these Frederickson et al. patents pertains to an improved
vibration isolating chain saw where a support means, including
handle means and inertia means, define a cradle-like structure
within which a vibrating assembly is resiliently supported. The
vibrating assembly includes a chain saw driving, internal
combustion engine and a guide bar and cutter chain assembly.
In the preferred embodiments described in the aforesaid
Frederickson et al patents, vibration isolating means are
interposed between the top of the engine assembly and underside of
the inertia means. Another vibration isolating means is interposed
between the bottom of the engine assembly and the support
means.
The structures featured in the aforesaid Frederickson et al patents
are believed to constitute a particularly significant advance in
the art of minimizing chain saw vibration. Nevertheless, and
particularly with respect to the lower vibration isolating mount
which is interposed between the support means and the underside of
the engine assembly, it is believed that significant improvements
may be yet effected.
For example, it is believed that it would be desirable to optimize
shock absorbing ability in a direction extending longitudinally of
the guide bar and cutting chain, i.e., longitudinally of the
cutting path, while maintaining a greater degree of stiffness,
coupled with a shock absorbing ability, in a multiplicity of
directions extending transversely of this longitudinal direction.
In particular, it is believed desirable to maintain this relatively
greater stiffness in a generally radial pattern, including both up
and down and side to side directions.
It is likewise believed desirable to provide an improved vibration
isolation unit which would yield the benefits of a diaphragm-type
shock absorbing action while minimizing the tendency of the
diaphragm to break or undergo damage due to prolonged usage.
It is likewise believed that it would be desirable to provide a
shock absorbing unit, particularly suited for use with a chain saw,
which would be resiliently operable in compression to absorb shock
in both up and down and side to side directions while maintaining
an ability to absorb cutter chain generated shocks, which are
oriented generally longitudinally of the cutting direction, in a
shear mode, and while attaining the foregoing desirable
objectives.
Bearing these overall objectives in mind, it is believed that they
are accomplished to a substantial extent in the context of a chain
saw having a vibrating assembly which includes an engine having a
crank shaft and also includes a cutter chain means which traverses
a cutting path. This chain saw context of the invention
additionally includes support means including handle means. A
plurality of vibration isolation means, in this type of chain saw,
serve to interconnect the vibrating assembly and support means.
The improvement aspect of the invention involves unique, structural
characteristics of at least one of the aforesaid vibration
isolation means.
Structural aspects of this improvement concept entail the use of a
resilient diaphragm means having an aperture and which extends
generally transversely of the cutting path. A shaft means passes
through the aperture of the diaphragm means, with the diaphragm
means being journaled upon the shaft means.
A first, resilient, impedance means, mounted on the shaft means,
abuttingly and separably engages one side of the diaphragm means. A
second, resilient, impedance means, mounted on the shaft means,
abuttingly and separably engages the opposite side of the diaphragm
means. A first mounting means connects the diaphragm means with one
of the vibrating assembly and support means. A second mounting
means serves to connect the shaft means with the other of the
vibrating assembly and the support means.
In a preferred arrangement, the resilient diaphragm means extends
generally parallel with the axis of rotation of the engine crank
shaft.
In the preferred embodiment, the diaphragm means includes a
mounting wall portion surrounding the aperture and the first and
second resilient impedance means define a generally annular recess
within which this mounting wall portion is both radially slideably
and rotatably received.
The wall portion may have flat parallel sides, with the generally
annular recess having flat parallel annular wall portions
contiguous with the flat parallel sides of the mounting wall
portion. Alternatively, the mounting wall portion may have a
convex, generally annular terminus surrounding the diaphragm means
aperture. In this arrangement, it is contemplated that the
generally annular recess would have a generally concave, outwardly
facing base, facing and engaging the generally convex terminus.
Another embodiment of the invention involves an arrangement where
each vibration isolating unit, interconnecting a vibrating assembly
of a chain saw with a support means, would be characterized by one
or more of various vibration isolation means structural
characteristics heretofore delineated.
As an independent aspect of the invention, and not limited to the
chain saw environment, it is contemplated that the invention
involves a vibration isolating unit characterized by the various
structural characteristics of a vibration isolation unit heretofore
set forth, either in the sense of the individual invention aspects
heretofore described or in the sense of the overall combination of
these distinguishing aspects.
In describing the invention by way of example, but not by way of
limitation, reference will be made to certain appended
illustrations set forth in drawings which comprise a portion of
this presentation.
DRAWINGS
FIGS. 1 thru 5 of the appended drawings illustrate various
structural aspects of preferred embodiments of the present
invention.
FIG. 1 schematically depicts a vibration isolation system of the
general type generally featured in U.S. Frederickson et al. Pat.
Nos. 3,542,095, 3,652,074, and/or 3,698,455 wherein the lowermost
of three disclosed vibration isolation units are fabricated and
installed in accordance with the present invention;
FIG. 2 provides an enlarged sectioned side elevational view of the
vibration isolation unit of the present invention which is
incorporated in the FIG. 1 assembly beneath an engine assembly and
above a lower handle portion;
FIG. 3 provides a transverse sectional view, in an enlarged format,
as viewed along the section line 3--3 of FIG. 1, and illustrating
the general mounting of the FIG. 2 vibration isolation unit;
FIG. 4, in a perspective and "exploded" format, illustrates the
separated components of the FIG. 2 vibration isolation unit;
and
FIG. 5, presents a modified form of the FIG. 2 vibration isolation
unit, again presented in sectioned, side elevation, and
illustrating a modified cooperation between the diaphragm means of
the vibration isolation unit and the resilient impedance means.
With the various drawing figures having been described, it is now
appropriate to consider structure aspects of the invention as
presented in these figures.
DETAILED DESCRIPTION OF INVENTION
Before treating the improvement aspects of the invention, a brief
summary of the preferred, chain saw context of the invention will
first be discussed.
PREFERRED CHAIN SAW CONTEXT OF INVENTION
The preferred arrangement for practicing the invention involves the
cradle-like vibration isolation systems featured in the aforesaid
Frederickson et al. U.S. Pat. Nos. 3,542,095, 3,652,074, and
3,698,455.
As set forth in each of these patents, a chain saw 1 includes a
vibrating assembly 2 including an engine assembly 3. Engine
assembly 3 includes a crank shaft having a rotational axis
generally depicted by the reference numeral 4.
Chain saw 1 additionally includes a cutter chain means 5 comprising
a guide bar 6 upon which a cutter chain 7 is slideably supported.
By virtue of driving means now well known in the art, engine means
3 serves to drivingly cooperate with the cutter chain means 7.
As is described in the aforesaid Frederickson et al. patents, the
vibrating assembly 2 is cradled within a support means 8. This
support means 8 may comprise a laterally extending handle means 9,
a longitudinally extended handle means 10, and an inertia or
dampening means 11. This inertia or dampening means 11 may comprise
a fuel tank.
The manner in which the components 9, 10, and 11 of the support
means 8 are structurally interrelated may be appreciated by
reviewing the disclosures of the aforesaid Frederickson et al
patents, the disclosures of which are herein incorporated, in their
entirety by reference.
A plurality of vibration isolation means serve to interconnect the
vibrating assembly 2 with the support means 8.
It is contemplated that at least three such vibration isolating
means would be employed, but obviously a number in excess of three
may be employed, depending upon the requirements of a particular
chain saw.
Thus, as is generally described in the aforesaid Frederickson et
al. patents, three vibration isolating means 12, 13 and 14 are
provided in chain saw 1.
The uppermost vibration isolating means 12 and 13, as shown in FIG.
1, are interposed between the top of the engine assembly 3 and
beneath the inertia or fuel tank means 11. The general arrangement
of the structure and mounting for these vibration isolating means
12 and 13 may be appreciated by making reference to the foregoing
Frederickson et al. patents.
The third vibration isolation unit 14, which may be interposed
between the top of the lower leg 15 of the handle means 10 and the
underside 16 of the engine assembly 3, constitutes the improvement
aspect of this invention and differs materially in a species format
from the lowermost vibration isolation units featured in the
aforesaid Frederickson et al. patents. The species difference
notwithstanding, it will be recognized that the general arrangement
depicted in FIG. 1 and described in this application corresponds to
the broader, vibration isolation invention described and claimed,
in particular, in U.S. Frederickson et al. Pat. No. 3,542,095.
Bearing these criteria in mind, it now becomes appropriate to
consider detailed aspects of the improved vibration isolation unit
14.
IMPROVED VIBRATION ISOLATION UNIT
Structural details of the improved vibration isolation unit of the
present invention are illustrated in FIGS. 1, 2 and 3, with respect
to one preferred embodiment. FIG. 4 further illustrates this
preferred embodiment in a separated component format.
As shown in these figures, vibration isolation unit 14 includes a
generally annular, resilient diaphragm means 17 having a central
aperture 18. As will be apparent from viewing FIGS. 1 and 2, the
plane of the diaphragm 17 extends transversely of the plane of the
cutting path defined by the guide bar 6 and and cutter chain 7 and
extends in the illustrated embodiment generally parallel with the
axis 4 of rotation of the engine crank shaft. A hollow shaft 19
passes through the aperture 18 of the diaphragm 17. However, the
diaphragm 17 is journaled upon the shaft 19 so as to be relatively
rotatable with respect to the shaft 19.
A first, resilient, generally annular impedance means 20 is fixedly
mounted on one end of the shaft means 19. This impedance means 20
serves to abuttingly and separably engage one side 21 of the
diaphragm means 17. A second, generally annular and resilient
impedance means 22 is mounted on the other end of the shaft means
19 and abuttingly and separably engages an opposite side 23 of the
diaphragm means 17.
The diaphragm means 17, and first and second impedance means 20 and
22, may be fabricated of synthetic or natural rubber or other
elastic material such as neoprene. The composition of the material
of the diaphragm may vary, depending upon the emperically
determined vibration isolation requirements of a particular chain
saw, as well as the conditions in which the saw must operate.
It is contemplated that the first and second impedance means 20 and
22 would be bonded to steel shaft means 19 by conventional,
elastomer-metal bonding techniques. Similarly a generally
cylindrical steel mounting ring 24 may encircle and be bonded to
the outer periphery of diaphragm means 17. In the preferred
embodiment, the outer periphery 25 of the diaphragm means 17
enlarges in each of oppositely directed longitudinal directions,
thereby affording optimum strength at the juncture between the
diaphragm means 17 and the mounting ring or cylinder 24.
Referring now to FIGS. 1 and 3, the mode of mounting of the
vibration isolation unit 14 may now be appreciated.
A first mounting means 26 may serve to rigidly connect the
diaphragm means 17 with the handle portion 15 of the support means
8.
As shown in FIG. 3, this first mounting means 26 may comprise a
generally "C" shaped mounting collar 27 having a concave, annular
mounting surface 28. This surface 28 is operable to conformingly
and contiguously engage the upper portion of the ring or cylinder
24. Threaded fastener means 29 and 30 may serve to clamp the
mounting "C" collar 27 to the handle portion 15 so as to in essence
clamp the ring 24 and diaphragm 17 rigidly to the portion 15 of the
support means 8.
This mounting arrangement may be facilitated, if desired, by
providing a recess or seat 31 on the upper portion of the handle
means 15. This seat may socketingly receive the lower portion of
the diaphragm supporting ring or cylinder means 24.
A second mounting means 32, depicted generally in FIG. 1 and 3, may
serve to connect the shaft means 19 with the vibrating assembly
2.
Second mounting means 32 may comprise a generally "L" shaped
bracket 33, welded to the underside 16 of engine housing portion 34
of the engine assembly 3. A tang-like portion 35 of bracket means
32 extends downwardly and is apertured to receive a mounting bolt
36. Mounting bolt 36 having a head portion 37, may pass through the
interior of hollow shaft means 19. A threaded fastener means, such
as a nut 38, may engage an opposite end of the threaded bolt means
36 so as to clamp the shaft means 19 rigidly against the right side
of the tang portion 35 shown in FIG. 1.
With this arrangement the bolt head portion 37 would abuttingly
engage the right end 39 of the hollow shaft means 19 (or a washer
means engaged therewith) while the left end 40 of the shaft means
19 would abuttingly engage the portion of the mounting tang 35
which encircles the aperture of the tang and through which the bolt
36 passes (or a washer means engaged therewith). Fastener 38 will
serve to clamp bolt 36 and shaft 19 fixedly to tang 35.
As will be appreciated, with this arrangement, the diaphragm means
17 will fluctuate or oscillate in a direction extending
longitudinally of the cutting direction of the cutter chain means
7, and will function in shear in this direction to absorb cutting
chain generated shock oriented in this longitudinal direction.
With respect to side to side (i.e., lateral) or up and down
movements of the chain saw, a compressive type interaction between
the diaphragm means 17 and the assemblies 2 and 8 will exist.
Vibrations oriented in up and down or side to side directions will
thus tend to be absorbed in a compressive mode.
Torsional interaction between the support means 8 and the vibrating
assembly 2 will be readily accommodated, without stress, by the
journaled relationship between the diaphragm means 17 and the shaft
means 19 which accommodates relative rotation therebetween.
Extreme fluctations, in a radial sense, of the diaphragm means 17
relative to the shaft means 19 will be uniquely accommodated in
view of the manner in which the diaphragm means 17 is radially
slideably received between the impedance means 20 and 22.
The presence of the impedance means 20 and 22, in contiguous
although separable engagement with opposite sides of the diaphragm
means 17, will afford unique shock absorbing action while
minimizing rupture or damage tendencies which would tend to occur
at any fixed juncture between these components.
The separable nature of the impedance means 20 and 22 relative to
the diaphragm means 17, and the journaled nature of the diaphragm
means 17 relative to the shaft means 19, may be best appreciated by
viewing the components of the vibration isolation unit 14 shown in
their separated condition in FIG. 4.
As shown in FIG. 4, the shaft 19 and the impedance means 20 and 22
constitute one separable component of the unit 14, while the
diaphragm 17 and mounting cylinder or ring 24 constitute another
separable component. When these two components are assembled, by
forcing the shaft 19 and one impedance means through the aperture
18, the assembled configuration shown in FIG. 2 is achieved.
In the assembled configuration shown in FIG. 2, the diaphragm 17
includes a mounting wall portion 41 which surrounds the aperture
18. The generally annular, resilient, impedance means 21 and 22
defined a generally annular mounting recess 42 within which the
mounting wall portion 41 is radially slideably and rotatably
received.
In the FIGS. 1 through 4 embodiment, the mounting wall portion 41
has flat parallel sides 43 and 44 surrounding the diaphragm
aperture 18. The annular recess 42 has generally flat, parallel,
annular wall portions 45 and 46 which are disposed in generally
contiguous relation with the flat parallel sides 43 and 44 of the
mounting wall portion 41.
ALTERNATIVE STRUCTURE
FIG. 5 illustrates a somewhat modified form of the vibration
isolation unit 14.
In this modified form a diaphragm means 17' is provided which has a
convex, generally annular terminus 47. This terminus has a central
aperture 18'.
Generally frusto-conical impedance means 20' and 22' cooperate to
define a generally annular recess 42'. This generally annular
recess has a generally concave, outwardly facing base 48 which
faces and engages the convex terminus 47.
It is believed that the hemispherical seat, "rolling" cooperation
between terminus 47 and recess base 48 may contribute to effective
shear type shock absorbing action in a longitudinally directed
orientation while uniquely prolonging the operating life of the
components of the vibration isolation unit.
With respect to either of forms of the vibration isolation unit
heretofore described, and with respect to other modifications
falling within the scope of the invention, it is contemplated that
in certain instances a journaled diaphragm type isolation unit of
this invention may be used in lieu of both or either of the
vibration isolation units 12 and/or 13.
As will also be recognized, a wide variety of mounting arrangements
may be employed for the installation of the improved vibration
isolation units of the present invention, i.e., the mounting
arrangement shown is depicted by way of example.
SUMMARY OF MAJOR ADVANTAGES AND OVERALL SCOPE OF THE INVENTION
In describing the invention various advantageous aspects have been
delineated.
A principal advantage of the invention is believed to reside in the
basic simplicity and ease of mounting and servicing of the improved
vibration isolation unit of the invention in conjunction with its
ability to undergo prolonged operating life.
Another major advantage of the invention is believed to reside in
the manner in which the journaled and separable nature of the
diaphragm means 17 relative to the impedance means associated
therewith, serves to prolong the operating life of the vibration
isolation unit while minimizing the tendancy for structural damage
to occur to the unit as a result of prolonged or intensive
vibration absorbing operation.
Other significant advantages of the invention are believed to
reside in the manner in which the improved vibration isolation unit
affords a unique, anisotropic shock absorbing action. In this
anisotropic shock absorbing action, cutter chain induced shock
and/or engine induced vibration, oriented in a generally
longitudinal direction with respect to the cutting path, is
absorbed in a shear phenomenon involving axially directed
oscillations of the diaphragm means. With respect to either lateral
or up and down interaction between the support means and the
vibrating means of the chain saw or any radially directed
interaction, shock or force is absorbed in a generally radially
uniform manner, with the components of the vibration isolation unit
operating in compression.
Those skilled in the chain saw vibration isolating art and familiar
with the disclosure of this invention may readily envision
additions, deletions, substitutions or other modifications with
respect to the disclosure heretofore set forth, all of which would
fall within the preview of the invention as set forth in the
appended claims.
* * * * *