US1812244A - Vehicle shock absorber - Google Patents

Description

E. H. KREIDER VEHICLE sHo'cK ABsoRBER June 30,l 1931.

Filed Aug. 6, 1929 Patented June 3o, 1931,]

fENo's H;knninnnfjorLANCASTEiENNsYnvaNIA i wnmiln 'snocx LNascanna i L inequalities .ofthe roadbed yandawhich" at the saine time will automatically 4r(ifi 'e.,I- without p manual interventionladj ust itself-to different vehiele loads, tofthe end that; wh atever the load inaybe' 'and-no Inatterfzhow. bei ehfglngeohy the lshook-absorbingeapaeities n" ofthe device a'slwellrasitrs,relieved Vvcenter action` will remain t( Fig. l is a horizontal ingA upwardly, an'dY r 1 Fig 2isaverticalftransverse sectional viewl of aideviceemb'odying a desirable orI'nofv r u .n n l. Y p for llillu'leatlng purposes.

' Anoil relief-passage; 29 extends fromfeach 1 i l pressure-chamber, through dierbaar-22, out a Figi: 3 is afdetail topvie.wofjthe valve-'cont-,iv

l trolling `devices ;v :fy

t, ft'1`1 l -wlatexoi'4 Y 'Flg 4 1S a' de al p an 0 i shall bel always-1n communication-With each other through the Voil-reservoir y. 14. The?" n *thepressure-chambersa i Figs; f-and vare ldiagrams s: partsl in :different vpositions 1 l 4horizontal rock-shaftk 12 which is connected' thisjflatficmetmg .meallSQ-,I'tt shaft 32vextends up'through the bar 22 and y being Shownbecuse l-t- 1S CQmmQn m t-hls wtf -f projects slightly ,beyond the` upper face of i said bar.- Each of the valves-Slis held noi'. Inally partially openv by an arrnf 35 'aiixed' to `vther aforesaidprojeeting lendtofrsaid roellz-V 1 shaft 32,` these two` arms' being held inH their Screwed to thewexterior of; the feylindrieal scre'w connection fbeing. ,provided by means of va serew-ring; 16 anda 1vpaching. v17. The' shat12fisfjournaled in 'a tubulartbearing `1 8 between .wh'oseouterendand the lshell 14a tight :j oint betweenshell 14. and ythe"` shaftf 12.

Y casing against a ooverplate' 21'lttedlinto the Owing; the hel'strainer. iReferring to the drawings *annexed* .reference vcharacters, .10 represents the oy- Y lindrical easing Whi'eh is provided j with the casing and extendingghoriz'ontally thereeasing l1 against anoutwardlyffacing inter-vv Anal shoulder. i 155i? The eover-plate f its'ldownvr against theupper` .L side ofa head-bar 22 fitted into the cylindrical g across; Within the chamber, underneath'theiv headbar 22, v-ibratesf the-vanepiston' 23 .i which is aiiixevdA to the innerend' of. the rock` shaft l12.,- the i outer edge ofzthisvane-piston f I working against the interiorv of vfthefcylinderf 10 in the`usualinnanneri and beingadapted tofV oseillate, in the usual mannenV with the shaft "12. The usual ehokefpass-ag'es -24 connectthe; `oil-chambers,at opposite. sides :of thepistonv Y to the interior Orf-theshaft 12, where a valve- .6? i

rseat 25is formed, soxthat the choke-passages 1 I inay bel eontrolledfbymeans ofa valve 26 arranged; axially in the shaft 122,- Certain adf f ditonal oilpassages ,Tand 28 are provided '76.

through the-outer `ace of the barfso that they' i i ingY Ythese oil-passages. 219,1outwardly-projecting pins `30- beingL provided onfthebarl l 22l `for Apositioning the Cover-plate s0 `as vto alwaysprevent itintefering Withtlieffree passagey of` oil through thesepassagesg29. 'Over'each of thefrelief--passages-29 `is;ar-'; ranged- :treed-valve 31 which/,is adapted 'tog spring to full-open/positiontoward its asso- 'ciatedpressureiohamben whoseailixed rocknorma-lposition (i. e., in position tofholdthe valve 31 laterally partially open)fbyrmean`s of 3 j a retraetile spring 36 which conneetsthearln's ,A35 and iholds said armsffnornially against'j`lr vstop-pins'37. 1Arran`ged gto' vibrate in'lthefA pathJof the outwardly-extending `ends ofarms isa pair yof fingers 38.carried{bya l sp'ring-olalnp 39 frictiofnallyYe'I'Vrllbraeing"the 21565' ""roek-shaft l2. ",lIn` order to maintain these .K y

fingers 38 in or near central position (i. e., in a position where the levers hold both valves partially open, as shown in Fig. 2), I provide a central pin 4() which projects rigidly from the outer face of the bar 22.

The disk 20 is provided with a plurality of holes l1 for the passage of oil from and to the relief-passages 29, and over all these holes is arranged a gauze strainer 4-2; the object of this arrangement is to prevent objectionable impurities entering the pressure chambers and thus interfering with the proper operation of the piston and valves.

With a normal load on the vehicle, the parts will be in the position shown in Fig. 2, in which position both valves 31 will be held partially open and the piston therefore will have a. greater freedom of action in either direction during minor vibrations, that is, so long as the vehicle is running on a relativelysmooth road and there is therefore no neel for bringing the shock-absorber into action. The instant, however, the wheel or wheels of the vehicle drop into a depression or are thrown up by an obstacle sufficient to impart ai major vibraiton, one or the other of the fingers 38 will swing its associated lever laterally far enough to swing its associated valve 31 to full closed position, while the companion valve 31 will remain open. In such case, the direction of movement of the piston will be toward the open valve, so that the initial movement, whether it be up or down, will not be materially hindered and the vehicle springs therefore will have just enough of resistance to stabilize their action. Upon return, however, of the piston, under the recoil of the vehicle-springs, the piston will move toward the closed valve and thus instantly set up an increased resistance against the movement of the piston, forcing the oil through the choke-passage 2st. Assumin an other major vibration or j ounce in the opposite direction, the same action will take place in a reverse order. In this operaiton of the device, the spring-band will not have any movement relative to the shaft on which it is clamped, as only in possible rare instances will the movei'nent be great enough for either one of the fingers 38 to strike Vagainst the central reacjusting pin 40. It will be observed further that the restraint is continuous throughout the entire correcting moveinent of the device, and that, if excessive road conditions are encountered on both sides of the relieved center area, the restraint of the device is continuous both ways, restaining right through the relieved center area but immediately partially opening both valves when 'the vehicle again begins to run on a relati vely-smooth roadbed. It will be seen further that during the period of time in which the valve 3l is closed and the vane 23 is moving to fard the same valve, the lever associated therewith will be free (so far as fingers 38 are concerned) to return to its original position with its valve 31 again in partially open position, but it will be understood that so long as the piston is approaching said valve the pressure of the oil against the valve will be sufficient to prevent the spring 36 acting to return the valve to its home position until the instant the movement of the piston toward the valve ceases, at which instant spring 3G will act to return the valve to its home, or partially open position.

It will be observed that each valve 31 consists of a plate of spring metal so that, even when it is in an entirely-closed position, as shown in dot-and-dash lines at the eXtreme right-hand end of Fig. 3, the valve is free to open inwardly by reason of the suction action exerted by the piston in ,its movement away from said Valve, so that in all cases the oil will have free access to each pressure-chamber whenever the piston is moving away from its valve 31. It is desirable to so arranged each reed-valve 31 that in lits homel position (shown in dotted lines at the left-h and end of Fig. it shall only partly cover its port 29 so that even an initial major movement of the piston toward the valve .will be more or less restricted, whereas in every movement of the piston away from the valve said valve offers practically no resistance to the entrance of oil through port 29.

In the foregoing description of the opera tion of the device, I have assumed that the vehicle is carrying a normal load and that the piston 23 is virtually at center, i. e., midway between the two valves. Should the load of the vehicle be increased or decreased, however, the piston will be shifted to one side or the other to a degree corresponding with the change in load, and the spring-band 39 together with its fingers 38 willbe carried with the rotation of the shaft 12 until they meet stop-pin 40, at which time the shaft will turn within the spring-band. rlhe piston will remain `in approximately this shifted position (which represents a new central position of the movements) so long as thel loadremains the same, and the spring-band with its iingers willalso remain in the shifted position until the vehicle has beenfdriven some distance, this distance depending generally upon the character of the roadbed. In any case, however, the slight jouncing of the axle will be sufficient to quickly restore the band and the fingers to central Vposition with respect to the pin l0 and the valve-operating levers. This shifting of the band back to 'central position will be caused principally by one of the lingers 38, name-ly, the one nearest the pin 40, repeatedly striking against said pin 40 until the band has been slid backwardly far enough on the shaft 12 to centralize the fingers with respect to said pin 40 (as shown in dotted lines in Fig. 6)',

after which the relieved center functioning will'be resumed withoutregard to whether the piston 28`is nearer to one` of the Valves 31 or the other. In this way, my device 'automatically (i.` e., without the intervention of any manual manipulations1 of `any ofthe parts) readjusts itself after each change of vehicle load, to the end thatwhatever the load be, the shock-absorberV functions in the same way as with what might be called a normal load, i. e., a load which would ceni tralize the lpiston 23.

In the diagram, Fig. 5, I show the initial position of the parts upon a load decrease, and in Fig. 6 I show the initial position ofthe parts upon increasing the load above normal.

What I claim as new isz:

l. In a vehicle shock-absorber of the hydraulic type embodying a rock-shaft carrying a vane-piston and means forming a pressure-chamber at each sidethereofQan inwardly-opening valve for each of these pressure chambers, devices for normally holding these valves open to thereby permit a freecenter movement of the vane-piston, and devices whereby a major vibration of the unsprung portion ofthe vehicle will rock the y said shaft sufliciently to positively close one of said valves while holding the other open.

2. In a vehicle shock-absorberof the hydraulic type embodyinga rock-shaft carry- Y ing a vane-piston and means forming a pressure-chamber at each side thereof, an inwardly-opening valve for each ofthese pressure-chambers, devices for normally holding these valves open to thereby permit a freecenter movement of the vane-piston, andV means whereby a major vibration' of the unsprung portion of the vehicle will rock the said shaft suiiiciently to positively close one of said valves while holding the; otherL open,

1 said'means embodying aV band frictionally e free-center position. -w

3. Ina vehicleshock-absorber of the hyembracing said rock-shaft and' carrying operating-fingers, and a device for aut-omatically shifting said band after a change of load on the vehicle-springs to returnsaid fingers to draulic typeembodying` a rock-shaft carryv ing a vane-piston and means forming a pres- 4 sure-chamber at each side thereof, an 1n-p v wardly-opening valve for each of these pressure-chambers, 'devicesl for normally holding Vthese valves open tothereby permit afreecenter movement of the 'vane-piston, yand means whereby a major vibration Yof theuni sprung portion of the vehicle willrock ther f said shaft suiiicientlyto positivelygclose one of saidvalves while lholding theother open, said means embodying avband frictionally i embracing said rock-shaft and carrying operfree-center position, said device consisting of a stopV located between said fingers.

4. Ina vehicle shock-absorber of the h l draulic-.type embodying a casing, a roc shaft' journaledA therein carrying a wing-piston, means in the casing forming a pressurechamber at each side of the plston, choke-pasfsages being provided for saidpressure-chambers and' also a relief-passage for each of said pressure-chambers, `a valve for each of said pressure-chambers opening inwardly with rec spect to its associated pressure-chamber, means for normally holding these valves open y during minor rocking operations .ofy said shaft and for alternately positively'closing said valves upon majorvibrations ofv said nov shaft, the construction' being such that said I centery position upon change of load on the vehicle-springs, and' a device whereby after the parts are shifted to abnormal position by change of load the subsequent vibrations of free-center position.

5. In a vehicle shock-absorber ofthe hydraulic type embodying a rock-shaft carrying a vane-piston and means forming a pressure chamber at each side thereof, an .in-

lmeans'will be yshifted out of'normal freen said shaft will restore the parts' tonormal y wardly-opening valve foreach of these p-ressure chambers, devices for normally holding each side of said vane-piston, choke-ports as y Y well as relief-ports being providedrfor each Ypressure-chamber, a--reed-valve for each relief-port, a rock-shaft carrying eachreedvalve, anV arm aiiixed' to each rock-shaft, a spring connecting thel arms of the rock-shafts to normally hold the reed-valves open, and `means,whereby amaj or vibration of the -unsprung portion of the vehiclewill rock one of said valve-,carrying rock-shaftssufficiently l to close its valvewhile leaving the other valve4 open.

y In testimony whereof I hereunto aiiixhmy signature.

ating-lingers, and a 'device for automatically f shifting said band after a changefof load on' the vehicle-springs to returnV said' fingers to.;

izo

Y Enos H; KREIDER.

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