CA1143390A - Vibration damper - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE

A vibration damper for a vibrational mechanical body, such as a chain saw or motorcycle, which is a source of vibration, comprises a support, such as an arm of the vibrational body for manipulation, a cylindrical grip mounted on the support, and a vibration-damping coiled spring having a row of small and large coiled portions and disposed between the support and the grip, with each of the small coiled portions being engaged with and supported by the support and each large coiled portion by the inner surface of the grip, whereby the vibration transmitted from the vibrational body to the support is absorbed by the vibration-damping coiled spring to control or lessen the vibration transmission to the grip. Instead of form-ing a continuous row of barrel-shaped units, the spring may be divided into such separate units or segments, or it may be replaced by a plurality of spiral unit springs for the same functions.

Description

BACKGRO~ND OF THE INVENTION
This inventlon relates to a vibratlon damper, and more specifically to a vibration damper for the handle or grip o~ a machlne, vehicle, or the llke which ls a ~ource of vibration, such as a chain saw or motorcycle.
The support for manual control o~ a chain saw, motor-cycle, or other vlbratlon-generating body is usually equipped with a cylindrical grip or the like for dlrect manipulation by the operator. Consequently, vibratlons ~rom the source are immediately transmitted to the support and the grip means, vlbrating the hand or hands of the user, o~ten so serlously as to impalr his health. For example, the vibrations of chain saws in cuttlng operations are widel~ known to be responsible ror Reynaud's dlsease.
Attempts have heretofore been made to 180}ate the vlbra-tions fro~. those ~aws, motorcycles, and other simllar sources to protect the human body. However, there has been no satisfactory solutlon proposed yet.
BRIEF SUMMARY OF THE INVENTION
It ls, therefore, an ob~ect of the presedh inventlon to provlde a vibration damper for the handles or grips Or chain saws, motorcycles, and other vlbration~generatln~
mechanlcal bodie~ thereby to protect the usèrs~agalnst Reynaud's dlsease and other lnJurious e~fect~ upon health.
A more ~peci~lc ob~ect of the lnvention is to provlde .~ ~

: ' ~43390 a vlbration damper which comprises a spring assembly Or a special construction through whlch a handle or grip is ~olned to a vlbratlonal mechanical body.
Wlth the vlbratlonal damper o~ the inventlon the vibrations, to be otherwise transmitted rrom the mechanlcal source to the user through the handle or g~ip, are sub-stantlally damped or abs'orbed.
The above and further ob~ects and ~eatures of the inventlon will be apparent ~rom the following detailed escription taken in connection with the accompanying drawlng. It is to be understood, however, that the description of the invention as applied to the handle or grlp Or a chaln aaw is for the purpos~e of illustratlon only and is not intended as a definition Or the llmits of the lnventlon.
BRIEF EXPLANATION OF THE DRAWINGS
FIG. 1 is a perspective view o~ a chaIn saw incorporat-lng a vlbratlon damper according to the invention;
FIG. 2 is a sectional view of a vibration damper embodying the inventlon;
PIG. 3 is a cross sectional view taken on the line I of FIG. 2;
: FIG. 4 is a sectlonal vlew Or anothe~'vibration damper :; ~ ., . ~ ~ , embodying the invention;

':: FIG. 5 is a cross sectlonal view taken on the llne :

~, II-II Or FIG. 4;
FIG. 6 is a sectional vlew of another embodiment Or the lnvention;
FIG. 7 is a cross sectional vlew taken on the line III-III Or FIG, 6;
FIG. 8 is a sectional view Or another embodlment;
FIG. 9 is a cross sectional view taken on the llne IV-IV Or FIG. 8;
FIG. 10 ls a sectlonal view Or still another embodl-ment;
FIG. 11 ls a cross sectional vlew taken on the line V-V of FIG. 1~; .
FIG. 12 is a sectional view Or yet another embodi-ment;
FIG. 13 i8 a cross sectional view taken on the line VI-VI of FIG. 12;
FIG. 14 i8 a sectional view Or a further embodlment;
FIG. 15 ls a cross sectional view taken on the llne VII~ Or FIG. 14;
FIG. 16 ls a sectlonal vlew Or yet a ~urther embodi-ment;
FIG. 17 is a cross sectlonal vlew taken on the llne VIII-VIII o~ FIG. 16;
FIG. 18 is a sectional view Or still a further emaodl-ment;

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'.' .

FIG. 19 is a cross sectional view taken on the line IX-IX of FIG. 18;
FIG. 20 ls a sectlonal vlew of an even further em~odl-ment;
FIG. 21 is a cross sectional vlew taken on the line X-X Or FIG. 20, FIG. 22 ls a sectional vlew of an addltional embodi-ment;
FIG, 23 ls a cross sectional view taken on the llne ~: XI-XI of FIG. 22;
FIG. 24 ls a sectional vlew o~ another embodlment;
; FIG. 25 ls a sectlonal view of the vl:bration damper Or FIG. 24 in use;
FIG. 26 ls a sectlonal vlew o~ another embodlment;
FIG. 27 ls a sectlonal view o~ stlll another embodl-. ment; and .~ FIG. 28 is a sectional view Or a rurther additional embodlment.c~ ..G. .,.
~ DETAILED DESCRIPTION OF THE INVENTION
.~ ~ Briefly stated, the vibratl~on damper accordlng to the lnventlon.comprises a support, such as an arm, o~ a vlbrational mechanicai body, a cylindri~cal grip or;:handle provlded concentrlc~ally Wlth the~support~ànd a~d~apted to be held by the hand o~ an operator ~or maDi~puiatlon? and a coiled or splral spring havlng small and ~rge coiled ~ ~ :

~ .

~ .

.

portlons formed alternately, the sprlng belng disposedbetween the support and the grip. Each small colled portlon is fixed to the support by weldlng or by sultable means such as a groove or rldge formed on the support, and each large colled portlon is engaged or contacted with the cyllndrlcal grip or handle. This constructlon remarkably lessens vibrations. If rubber or other reslllent material is employed, for example, as part of the cylindrlcal grip, the damper will attain a higher degree of vibration dampin~ or absorption. The spring of the special configu-rations as described above may comprise either a slngle length with the alternate bulges and constrictlons or a plurality of separate segmental or unit springs, each consisting of at least one large coiled portion and at least one small coiled portion. Also, the sprlng may be secured to the grip and the support by welding, grooving, bonding with adheslve, etc., or alternatively it may be retained between the cylindrical grip and the support by means of flanges formed at the both ends of the grip. As a further alternative, an inner cylinder may be provided instead of directly fixing the spring to the support or havin~ lt engaged wlth the latter. In thls case, the erip, inner cyllnder, and spring can be integrally assembled in advance~
In FIG. 1 there ls shown'~ in perspective, a chain saw 'i' _ 5 -adapted to lncorporate the vlbration damper of the invention.
The numeral 1 designates a houslng accommodatlng the drives, hereinafter called the vibrational body because it con~tltutes a source Or vibratlons. The saw blade ln the ~orm of an endless chain is indicated at 28. The vibrational body 1 includes a support 2, such as an arm, to be gripped by the operator. A grlp or handle 3 ls sleeved over an upper portion of the support 2. The vibration damper accordlng to the lnvention pertains to a structure ~oining the support 2 and the grip 3 together. Thls applies to all of the embodlments now to be descrlbed in detail.
Referrlng now to FIGS. 2 and 3, one embodlmènt of the inventlon 1~ illustrated. Throughout the~e and all other ensulng figures similar reference numerals lndicate slmilar members or portions. On a tubular support 2, such as an arm~ o~ a vibrat~lbody ls fitted a spring cons~isting o~
a row of barrel-shaped sprlng unlts 4, held in place by weldlng or other connecting means, such as grooves and stopper ridges formed on the support. This sprlng comprises an axial row of barrel-shaped unlts as shown, each unlt s~tarting wlth a neck or constrlctlon, bulging mldways, and agaln~narrowing down to form the startlng port~o~or the next-unlt in a cycllc arrangement. The enve ~ of the spring has slnusoidal or deformed s~ usoldal contours.
Since~the sprlng has a plurallty Or constrlctions Or the ~433~0 same diameter, it can be directly secured to the support wlthout the aid Or other ~oining means. 0~ the other hand, the plurality of bulges of the same d~ameter may be fixed to the inner surface of an lnner cylinder 5' of metal, which in turn is fitted to the inner surface of the grip 3. In this way the spring comprising the barrel-shaped spring units 4 of alternate bulges and constrlctions permits the grip to be fixedly mounted on the support to effect vibratlon damplng. The inner cylinder 5' of metal is fitted ln, or covered wlth, an outer sleeve 5 of vulcanized rubber or other resllient material, the both comblnedly constltuting the ~ylindrical grip 3. The outer sleeve 5 is formed wlth flanges 71~ 72 at the both ends for contact with the both extremltles 61, 62 f the spring to keep the latter from moving axlally. Thus lt has some ~ibration damplng or absorblng action, pro~ides adequate frictlon for gripping, and prevents removal of the spring by means of the flanges 71~ 72. Where desired, the spring may be cut off at given points of either the constrlcted or bulged portions into separate segmental springs.
FIGS. 4 and 5 show another embodiment of the vlbration , ,~
damper accordlng to the invention.~ Here, the ~pring is likewi~e secured to the support 2 and ls 8 ~ in ``~ structure to that of the embodlment lllu~trated ln FIGS.

2 and 3 except that lt end~ at 61, 62 wlth bul~es lnsteaù.
I

33~0 Also, the grip 3 in this embodiment is made of a single metal cylinder, whlch ls bent at ends perpendicularly to the axls to form annular flanges 71 " 72' for restrlctive engagement with the bulged ends 61, 62 of the spring. The grip 3 ln the form of a sleeve restrlcts the axial move-ment of the spring and prevents it from slipping off.
Another embodiment Or the invention is shown in FIGS. 6 and 7. Unlike the preceding embodiments, it has an inner metal cylinder 8 dlsposed between the tubular support 2 and the coiled spring having alternate constric-tions and bulges and simllarly flxed to the support. The both ends of the inner cylinder are bent up at right angles to the axi~ to hold the opposite ends 61, 62 f constrictions of the spring unremovably. An outer metal cylinder 8', which ~orms the cyllndrlcal grlp 3, is flangeless and is secured by welding or the like to the bulges of the spring. Thls embodiment is easy to manu-facture, because the lnner and outer cyllnders 8, 8' and the spring in a row of barrel-shaped units can be assembled beforehand and flxed as such to the support 2 to complete the necessary mounting work.
FIGS. 8 and 9 show still another vlbration damper embodylng the inve~tion. Here an inner metal cyllnder 10 ha~ upright flanges 131, 132 engaged wlth constricted ends 61, 62 f a sprin~ to hold the latter unmovably. In ~i~339U

additlon, the metal cylinde~ has cylindrical extenslons lll, 112 flxed to the support 2 by cap screws 12l, 122, respectlvely. An outer cyllnder lO', constltuting the grip, ls formed of resilient materlal, such as hard rubber, to provide a burfer and an adequate friction for the hand of the operator.
In FIGS. 10 and ll ls shown an embodiment slmilar to the one shown ln FIGS. 8 and 9. The only dlfference ls that the grlp 3 Or thls embodiment conslsts of a rubber cylinder lO' and a metal cyllnder 14 fltted inslde as a lining, to whlch the sprlng is secured. In thls case the rubber material may be sorter than the counterpart in FIGS. 8 and 9.
Another embodiment is shown in FIGS. 12 and 13. Llke all Or the precedlng embodlments lt has a coiled sprlng 4 wlth lts constrlctions secured by sultable means to the tubular support 2. The bulges of the spring are banded to the lnner surface of the grlp 3 made of hard rubber or other resllient material. The both ends of the grip 3 are rormed with flanges 71~ 72. A digtinct feature Or this embodlment ls a plurallty Or nonslip,~ ringlike lands ~ormed on the outer perlphery or~t~e grip 3. The lands . . . ~. . .
enable the operator~to take a~rirmer grip, with some damp- -lng effect in addit-ion to the vibratlon-lsolating erfect of the c~dsprlng.
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_ g _ ~JL i i~43~90 A simllar embodiment of the invention ls given in ~I¢S. 14 and 15. Its grip 3 consi~ts Or a hard rubber cyllnder having end flanges 71~ 72 and also a plurality o~
nonslip lands 15' of sponge rubber provided on the outer perlphery Or the rubber cylinder. This structure ls more ef~ectlve in lessenlng the transmis~lon of vlbration~.
FIGS. 16 and 17 illustrate another embodlment, in which the spring is divlded in~o separate barrel-shaped segments 4, each having a constriction and a bulge and fixed to the tubular support 2. The grlp ls concentrically , mounted on the spring. As shown~j t~e~gri~p~-3 1s~ a cylinder o~ hard rubber havlng a plural$ty of rlngllke ti~rening -rlbs 16 formed on lts inner su~faoe.~.In-rlnglikc recesses 16' rormed by the rlbs, the bulges oP the~sprlng~segments ~, are fltted ~ecurely ln place. -~

In a further embodlment o~-bhé invent~on;shown in !i,~,;' ~ ' FIGS. 18 and 19, a pair of splral springs 4 are fl~ed to ~ the tubular support 2, spaced apart at two points along, ~ .
.
~- and in planes at rlght angles to, the axls Or the support, by sultable means. Around thQse sprlngs ls fltted a grip

3, eonsisting Or a~metaI cyli~ ~ 5'~and~ an: ou~er cylinder 5 of rubb~er or other resl~lie ~ at~erla;l~ ~ta ~ d-~t~o the ;c~llnder and ha~lng~rlanges ~ 7z ~orme~ ~r ~ oslte ends.
Although the springs are co~rled to conrl-~ratlons unllke those ln the embodiments~so far described, they~achieve . .
'''' ~43390 the same vibration damping effect as by the preceding ones.
Yet a further embodiment i8 shown ln FIGS. 20 and 21.
The sprlngs 4 are slmilar to those ln FIGS. 18 and 19 but, ln order to retain them in the space between the support 2.nand the m~tal cylinder 5', the support ls formed with annular grooves 20 on the outer periphery and the metal cylinder is formed with corresponding annular grooves 21 on the inner surface, so that the both ends 18, 19 Or each spring are fitted in each set of those grooves. In this way the damping portions and the grip are positively secured in position.
An even further embodiment of the invention, shown in FIGS. 22 and 23, uses spiral sprlngs 4 coiled in the same way as those in FIGS. 18-21 but are made o~ narrow, flat bands X~X instead o~ round wires.
FIGS. 24 and 25 illustrate another embodlment, in which the spring 4 has a plurality of barrel-shaped unlts with alternate constrictions and bulges of given diameters.
The constrictions are fixed to the tubular support 2.
~oncentrically with the support, an elongate, barrel-shaped grip 3 i9 mounted thereon. It consists Or a rubber cylinder havlng hollow sections 22 varied stepwise in diameter and a complementary, reinforclng metal cylinder 23 of corresponding configurations fitted tight in the .
, ~1~3390 -rubber cylinder. Thus the lnside dlameter Or the metal cylinder 23 increases, sectlon after sectlon, from the bvth end~ toward the middle portion. As lndicated, only the bulges Or the barrels near the both endæ of the sprlng

4 are fixed to the metal cylinder 23. Therefore, while the magnitude of motlon or vibratlon from a machlne or the like as the source ls small, the end spring sectlons wlll absorb lt. As the magnltude lncreases, the other spring sections will, one after another, take part in the vlbratlon damping as shown, for example, in FIG. 25. The advantages of this embodlment are the comfort with which the operator can grlp the damper and the smooth increase or decrease of vlbratlon damplng ln proportion to changes ;
in the magnltude of vibratory motion.
FIG. 26 shows yet another embodlment Or the inventlon.
This vlbratlon damper includes a coiled sprlng 4 ln a row of barrel-shaped unitæ provided around the tubular support 2. The spring is covered by a grip 3 consisting of a stralght outer cylinder 5 of rubber formed with flanges 71~ 72~ and ~e~ata~Jcylinder-5' fitted as a linlng for relnforcement. The bulges o~ the ~ring barrels are progresslvely reduoed ln diameter from the both ends toward the middle portlon~o~ the sprt~g~ Co~sequently, the damper functlons ln use in the~same manner as that of FIGS. 24 and 25.

FIG. 27 shows another embodiment as a modlfication Or that which is lllustrated in FIGS. 18 and 19. Similarly, the spiral springs 4 in a palr are located innthe same planes normal to the axis of the support 2, but thls arrangement dlffers from the prevlous one in th~t the lnner and outer ends of each spring are coiled double to ensure posltive fixing to the support 2 and the reinforc-ing metal cylinder 5'.
A further additional embodiment shown in FIG. 28 utilizes the splral springs of FIGS. 18 and 19 but retain them in a different way. Tne support 2 is rormed wlth two annular grooves ln spaced relatlon, collars 271, 272 are fitted in the grooves, and the vibration-damping unit sprlngs are kept in pressure contact with the inner sldes of the collars facing each other. On the other hand, the grip 3 conslsts of a small-diameter, re$nforclng~metal-cyllnder 24 having large-diameter, flared ends 261, 262, and a rubber cyllnder 25 snugly fltted in the thus-recessed outer periphery of the metal cylinder. Each unit spring is engaged on one side with the annular step deflned by the flared end of-the metaI cylinder. These steps coact with the collars to retain the springs- unremovably in place.

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~ 13 ;

.~ :

Claims (11)

1. A vibration damper for a grip of a vibrational mechanical body which vibrates during operation, such as a chain saw or motorcycle, the vibration damper comprising a support on said vibrational body for manipulation such as an arm, a rigid or relatively rigid cylindrical grip mounted on said support and a plurality of vibration-damping springs disposed between said support and said grip, each spring consisting of at least one small coiled portion, at least one large coiled portion and at least one conically and spirally coiled portion extending from the small coiled portion to the large coiled portion, at least each of said conically and spirally coiled portions being formed by a plurality of spaced turns of coil, said small coiled portions being secured to the support and at least pairs of small or large coiled portions at the axial extremities being secured to the inner surface of said cylindrical grip.

2. The vibration damper of claim 1, wherein said cylind-rical grip consists of an outer cylinder of rubber or other resilient material lined with an inner cylinder of metal, and said vibration-damping coiled spring is divided into a plurality of barrel-shaped-units arranged in an axial row, with the both extremities of the spring being engaged with and supported by flanges formed at both ends Or said outer cylinder.

3. The vibration damper of claim 1, wherein said cylindrical grip consists of a single metal cylinder, and the both extremities of said vibration-damping coiled spring are engaged with and supported by flanges formed at both ends of said metal cylinder.

4. The vibration damper of claim 1, wherein said cylind-rical grip consists of an inner and an outer metal cylinders held a suitable distance apart, and the both extremities of said vibration-damping coiled spring disposed in said space are engaged with and supported by flanges formed at both ends of said inner metal cylinder.

5. The vibration damper of claim 1, wherein said cylindrical grip consists of an inner metal cylinder and an outer cylinder of rubber or other resilient material suitably spaced apart, said inner metal cylinder having cylindrical extensions from both ends and secured thereat to said support by cap screws and also formed with flanges at the both ends by which the both extremities of said vibration-damping coiled spring disposed in said space are engaged and supported.

6. The vibration damper of claim 1, wherein said cylindrical grip consists of an inner metal cylinder and an outer cylinder of rubber or other resilient material suitably spaced apart, said inner metal cylinder having cylindrical extensions from both ends and secured thereat to said support by cap screws and also formed with flanges at the both ends by which the both extremities of said vibration-damping coiled spring disposed in said space are engaged and supported, said outer cylinder of resilient material being lined with a metal cylinder.

7. The vibration damper of claim 1, wherein said cylind-rical grip consists of a cylinder of rubber, synthetic resin, or other resilient material formed with a plurality of nonslip, ringlike lands on the outer periphery for ease of gripping.

8. The vibration damper of claim 1, wherein said cylindrical grip consists of a rubber cylinder having a plurality of nonslip lands of sponge rubber formed on the outer periphery for ease of gripping.

9. The vibration damper of claim 1, wherein said cylindrical grip consists of a rubber cylinder having a plurality of ringlike stiffening ribs formed on the inner periphery, and bulges of barrel-shaped units of said vibration-damping coiled springs are engaged with and supported by ringlike recesses formed between said stiffen-ing ribs.

10. The vibration damper of claim 1, wherein said cylindrical grip is a thick-walled rubber cylinder having hollow sections reduced in diameter stepwise from the middle section endways and lined with a reinforcing metal cylinder.

11. The vibration damper of claim 1, wherein said cylindrical grip is a straight cylinder of rubber lined with a reinforcing metal cylinder, and said vibration-damping coiled spring consists of a plurality of barrel-shaped units progressively reduced in diameter from the both ends toward the middle portion of said spring.