US2259730A - Multiclutch mechanism - Google Patents

Description

Oct. 21, 1941. E. R. BURTNETT MULTICLUTCH MECHANISM Filed Feb. 2, 1938 Patented Oct. 21, 1941 MULTICL'UTCH MECHAN ISM Everett R. Burtnett, Los Angeles, Calif., assigner of one-half .to Edith Glynn Burtnett,y Los Angeles, Calif.

Application February 2, 1938, Serial No. 188,218

32 Claims.

This invention has to do with a clutch mechanism, and it is particularly directed toward the provision of a clutch mechanism operable by centrifugal action. Such a clutch is useful in automotive vehicles and the same is described herein in such an environment, but it Will be obvious that the clutch mechanism-may be employed elsewhere than in'automotive vehicles.

One of the principal objects of the invention is, the provision of a centrifugal automatic clutch mechanism wherein a priming centrifugal clutching action initially takes place; wherein a secondary centrifugal clutching action comes into play thereafter at a higher R. P. M.; and wherein both the priming or initial and the secondary centrifugal actions operate collectively to pack the respective clutch engagements at a coeiiicient which will maintain a high torque capacity at an R. P. M. lower than that'speed at which the secondary centrifugal clutching effect may respond to come into play.

Another object of the invention is, the provi-e sion of a centrifugal automatic clutch mechanism with a first distinct system of centrifugal acting means to start the clutch engagement-packing of a given system of clutchable elements and a second distinct system of centrifugal acting means for completing the clutch engagementpacking of the given system of clutchable elements, respectively, whereby the initial centrifu gal clutching action is, for example, gradual in accordance with accelerating R. P, M. of the driving member and whereby the subsequent secondary centrifugal clutching action may be appreciably relatively faster in attaining a given torque capacity than that ordinarily required to centrfugally produce such torque capacity.

Another object of the invention is, the provision of a multi-clutch mechanism wherein a plurality of distinct centrifugal systems form means individually operative to cause certain clutch forming means 4whereby complete packing of the given multiple clutching system under the initial packing-centrifugal means is restrained until an abnormally high R, P. M. has been attained at which the initial packing centrifugal means may have'a coetlicient such that, when released by the dead center toggle linkage, may immediately pack the entirety of the multiple clutching system at a full torque capacity. And, to the end of controlling the dead center toggle means, the present invention further contemplates the provision of a distinct system of speed responsive means together with a distinct system of resilient means collectively forming means for normally urging the dead center toggle linkage into and to rest in dead center toggle relation whereby the restraining action which it is designed to effect is incurred, but to respond to a predetermined speed of rotation with the effect of causing the collapse of the dead center toggle against the influence of the resilient means whereby the restraining effect of the toggle linkage is both timed and actuated out of play.

Another object of the invention is, the provision of a centrifugal automatic clutch mechanism provided with a multiple clutching system associated with a given initial acting system of clutch engagement-packing centrifugal means and provided with an expandable unit of frictionally-engaging elements connected to rotate as a unit but arranged and adapted to normally standstill and be initially engaged by a priming frictionally-engaging driving clutch element thereto. The latter to be actuated by the given associate system of initial acting centrifugal means, whereby the normally still unit of expandable clutch elements may be excited to rotate from a standstill up to the speed of the engaging driving member immediately and accordingly immediately develop a high torque clutching capacity. And, to the end of developing said high torque capacity in the unit of expandable clutch elements under this immediate speed attainment from a. standstill corresponding to the speed of the driving member, the present invention further contemplates the provision of a. distinct system of centrifugal weights carried by, and for causing the expanding of, the unit of expandable clutch elements whereby the centrifugal clutch packing coefficient corresponding to the speed of a priming driving member may be reached as rapidly as that of the rate of acceleration of the unit of expandable clutch elements from their state of standing still to their primed 4of a multi-clutch mechanism, provided with speed responsive automatic means for clutch engagingly packing first one and later another of the clutchable units of the multi-clutch mechanism, and with means provided for optionally, either preventing clutch packing engagement of the clutch mechanism under the normal influence of the speed responsive automatic means, or causing disengagement of the multi-clutch mechanism from its speed responsive automatic means clutch-packed engaged state. And, to the end of providing for preventing, or for causing disengagement of, clutch-packed engagement of the multi-clutch mechanism under the influence of the speed responsive automatic means, the present invention further contemplates the provision of a distinct optionally disengageable clutch unit of frictlonally engaging elements forming a bottom pressure element to the multiple of speed responsively automatic engageable clutch units of the multi-clutch mechanism, with automatic but yielding means provided to normally close this distinct optionally disengageable clutch unit, and with means provided for forcing the yielding means to yield with consequent opening of this clutch. All such that the normal bottom pressure effectiveness of this optionally disengageable clutch unit to the multiple of speed responsive automatic clutch units is withdrawn such that all the speed responsive automatic clutch units of the multi-clutch mechanism are rendered nonpackable into clutch engagement by the speed responsive means.

Still another object of the invention is, the provision of a multi-clutch mechanism` combining'a positive type centrifugal automatic clutch mechanism and a friction type spring-meansnormally-engaged clutch mechanism both operating to complete driving connections of a given train of power transmitting members. The positive type centrifugal automatic clutch unit of which combination being preferably for cooperation with a planetary gear unit which would afford rotation of the centrifugal element of this clutch unit only upon the torque being reversed from that at which the load is propelled through such planetary gear unit. The normally engaged friction clutch mechanism of this combination being adapted to normally complete the driving connections of the train upon the positive type centrifugal clutch becoming engaged under the rotation of this reverse of torque. The friction type clutch mechanism forming a clutch mechanism adapted to be optionally opened to effect a break in the united planetary gear unit such that would permit the positive type centrifugal clutch, once engaged or united, to come to rest with its released associate element of the planetary gear train and thus disengage. Whereupon, the speed ratio of drive, in effect before the engagement of the positive type centrifugal clutch unit, would again come into play.

Other objects of the invention reside in the provision of a simplified multi-clutch mechanism structure wherein parts are minimized and wherein, more specifically, centrifugal members function as clutch engagement packing actuators and as devices timing secondary clutch engagements such that higher than ordinary speeds of rotation are attained before initiating said secondary clutch engagements.

The accompanying drawing is a vertical longitudinai section taken through a multi-clutch mechanism constructed in accordance with the invention, and shows also a gearing which, is exemplary only of one form of associate power transmitting means, in conjunction with which the multi-clutch mechanism would cooperate advantageously.

As above set forth the invention is shown and described in the environment of an automotive vehicle. Accordingly, the fly-wheel of an internal combustion engine is shown at I0 to rotate with the end of an engine crank shaft II. A driven power transmitting member is illustrated at I2y and adapted to be connected to the vehicles driving wheels to propel same. The usual clutch shaft element of the drive is illustrated in a multiple of four concentric members comprising a low or rst speed shaft I3, a second speed shaft I4, a third speed shaft I5 and a fourth speed (direct drive) shaft I6, all forming intermediate shafts with respect to their disposition relative to the driven shaft I2 and the engine crank shaft II which latter may be termed the driving member.

An exemplary multi-speed gearing which would cooperate'with each of the multiple of clutch shafts I3, I4, I5 and I6 is shown in conjunction with the present multi-clutch invention, and such gearing with which the multi-clutch mechanism would cooperate advantageously, is illustrated as follows: A planet carrier I'l rotatable With the driven shaft I2, a planet gear cluster I8 mounted upon the planet carrier I l and comprising integral large and small planet gears I9 and 20, a large sun gear 2I rotatable with the clutch shaft I4 and meshing with the smaller planet gear 20, a smaller sun gear 22 meshing with the larger planet gear I8 and to be driven from the clutch shaft I3, and an internal gear 23 forming a distinct pivotal element meshing with the large planet gear I9 constitutes one planetary gear unit operative to drive the driven shaft I2. A second planet carrier 24 is rotatable with the internal gear 23; a distinct planet gear element 25 is mounted upon the second planet carrier 24; a sun gear 26 is rotatable with the clutch shaft I5 and meshes with the second planet gear 25 and a second internal gear 21 forming a distinct pivotal element and meshing with the second planet gear 25 constitutes a second distinct planetary gear train. A transmission case 28 shown integral with a clutch housing 29 has integral portions 30 and 3l respectively for-ming stationary annulus elements to separate overrunning brake units 32 and 33. The overrunning brake unit 32 comprises the customary roller brake members 34 and the customary cams 35 formed on the hub portion 35 of the second internal gear 2l and operates to prevent rotation of this internal gear 21 backwards. While the overrunning brake unit 33 comprises the customary roller brake members 3l and the customary cams 38 formed on the hub portion 39 of the internal gear 23 and operates to prevent backwards rotation of this internal gear 23. The clutch shaft I3 is constructed separate of the sun gear 22. An overrunning clutch comprising, a driven annulus 40 integral with the sun gear 22 and the customary cams 4I formed on the periphery of the clutch shaft I3 and roller clutch members 42 forms a one-way drive means between the clutch shaft I3 and the sun gear 22. It will be seen that forward driving by the clutch shaft I3 first will cause forward one-way driving of the sun gear 22 through the medium of the overternal gear 23 and by virtue of the latter being prevented from rotating backwards by the vroller brake members 31 causes the planet carrier I 8 and integral drivenshaft I2 to be forward driven at reduced speedgiving a first'speed ratio.

It follows, that under drive taking place subsequently through the shaft I4 the smaller planet gear 2|) will be caused to rotate reversely by the larger sun gear 2| with the result that the planet gear I3 will be rotated faster than heretofore. This will cause the smaller sun gear 22 tractive clutch springs 5I. `The most rearwardly of the driving clutch plates `48 serves`r as a rearward final bottom pressure plate.

A shoulders: in the clutch sneu provides a'. l

-suitable stop limiting the movement of the driving plate 46 and upon which the latter is adapted to rest normally. To the end of causing the plate 46 to normally rest against the shoulder`- 52, a spacer 53 is arranged in the clutch shell 43 to seat rearwardly against the driving clutch plate 41, and secondary retractive springs 54 are compressed fbetween the plates 46 and spacer 53 such that the plate 46 normally but yieldingly rests against the shoulder 52 and such that, through the medium of to rotate faster than its individual driving clutch the spacer 53, the plate.- 41 is constantly urged shaft I3 as permitted by the overrunning clutch rollers 42. In other words the supplantation of the drive of the sun gear 22 by the drive of the sun gear 2I. The consequent faster rotation of the planet gear I3 will carry same around its gear track in the internal gear 23 at a higher speed and result in the planet carrier I3 and the integral'drive shaft I2 being stepped up from first to second forward driven speed ratio.

Up to this time the planet carrier 24 has stood still with its integral internal gear 23 operating as a 'respective member under drive rst from the clutch shaft I4 and then the` clutch shaft I3. Upon the clutch shaft I5 being connected to rotate with the driving member IIas a unit with the already connected clutchshafts I3 and I4 thereto, it will be seen that the planet gear 25 will rotate reversely and run around its gear track in '20 the driving plates 41 and 48.

rearwardly toward the rearward final bottom pressure plate 4B. In rotation with. the fourth speed clutch shaft I6 is a driven clutch disk 55 disposed to be clutch engagingly packed between Since the master retractive springs 5| operate to constantly Iurge the plate 48 forwardly and since the secondary retractive springs 54 constantly operate to urge the plate 41 rearwardly, the fourth speed (high) 25 driven disk 55 is normally clutch springpressure-packed between the plates 41 and 43, giving the internal gear 21 because of the latter beingv prevented from rotating backwards by the brake rollers 34. This will result in the planet carrier 24 and its integral internal gear 23 being driven forwardly at reduced speed with the result that the individual gear track ito the planet gear I3 will rotate forwardly carrying the planet gear I9 with it. Since the planet gear Iiiv is also under forward drive by the sun gear 2 I, the speed of the planet carrier 'I8 will obviously be stepped up as a result of the second planetary gear unit coming into driving play. The two planetary gear units thus set into collective gear train driving operation, as a result ofthe third clutch shaft I5 adding to the drive, changes the speed ratio of drive to the driven shaft I2 from that of second to third. If the fourth clutch shaft I6 were to be connected to rotate with the driving member II, together with the other three clutch shafts I 3, I4 and I5, and if then or thereafter the clutchi shaft I6 and the internal gear 21 were to be connected to rotate together, it will be seen thatthe planetary gearing iny its entirety comprising both distinct planetary gear units would become locked into a unity to rotate in mass forming a direct drive of all the clutch shafts I3, I4, I5 and I6 and the planetary gearing between the driving and driven shafts II and I2, giving the ,fourth speed ratio of drive to the driven shaft I2.

On the premise of this relationship between the four clutch shafts and the exemplary formvoi gearing shown, the present multi-clutch mechaonism invention is described as follows: I

A clutch shell or ydetachable part of the flywheel I0 is indicated at 43. Within and rotatable with but mounted for` longitudinal movement relative to the flywheel I6 are multiple driving clutch plates 44, 45, 46, 41 and 48 enclosed at the front end by the disk portion of the flywheel I0 forming a final forward bottom pressure plate 49 and at the rearward end by a -back portion 50 of the clutch shell 43 forming a base for master rea conventional normally but .yieldingly engaged clutch effect. A stop indicated at 56 limits the movement of the spacer 53 and in turn the plate 41 such that, influenced by the springs 54, the plates 46 and 41 will normally rest at a fixed distance longitudinally apart. t

So thatvthe fourth speed driven clutch disk 55 may be unpacked, that is to say this clutch unit released, at-the option of the driver, the customary clutch release fingers 51 acting upon studs 58 threaded into apertures provided in the rearward final bottom pressure plate 48 are provided, and the customary clutch release or throw-out bearing 53 for actuating the release fingers 51 is also provided to actuate the fingers 51 forwardly at their inner ends to pull the plate 48 rearwardly..

Since the fourth speed clutch shaft I6 is shown to normally be connected by means of the above described normally engaged but optionally disengageable friction clutch, and since to effect the fourth speed, that is to say complete the driving connections of the fourth speed, the internal gear 21 must be connected to rotate with the clutch shaft I6. The present invention contemplates the provision of a positive type centrifugal auto' matic distinct clutch unit preferably operating between the internal gear 21 and the clutch shaft I6. A desirable adaptation of a positive type 55 centrifugal automatic clutch at this point would be one the centrifugal actuating means of which was carried by the internal gear 21. For, since the internal gear 21 normally stands still or at yleast normally rotates at a speed relative to the clutch shaft I6, and since the internal gear 21 is adapted to respond to a reverse of torque and accelerate up to or beyond the speed of the clutch shaft I6, this could advantageously provide that the centrifugal means would not function to 55 engage the clutch and connect the clutch shaft I6 and internal gear 21 until the torque had been reversed and then not until the driving and driven parts, respectively, ,clutch shaft I6 and internal gear 21 had attained synchronous speeds. This therefore, would leave the third speed ratio of drive operable at any vehicle speed attained under acceleration at the option of the driver to permit automatic shift to fourth by momentarily decelerating the engine to promote the momentary reverse of torque required to accelerate the internal gear 21 and centrifugal clutch actuating means responsive thereto. A suitable form of positive type centrifugal automatic clutch for this adaptation is indicated at f and comprises clutch teeth 60 on the fourth speed clutch shaft I6, a f

longitudinally shiftable clutch member 6I spllned as indicated at 62 to the internalfgear ,21 and shiftable from its normal resting position (shown) forwardly until the splines inthe bore of the shiftable clutch member 6I engage and mesh-overlap sufliciently in the driving clutch teeth 60. So that the clutch member 6I will normally rest retracted out of engagement with the shaft I6, retractive springs 63 are provided to urge a stud 64, the latter threaded into aC flange portion 65 of the clutch member 6I, and in turn the clutch member 6I rearwardly. The stud 64 passed through a flanged portion 66 of the internal gear member 21 and lends compression action to the spring 63 against a washer 61 limited (by any suitable means such as a pin through the stud behind the washer 6l) in movement over the stud rearwardly, To actuate the clutch member 6I forwardly into engagement with the clutch teeth 60 of the shaft I6 upon the internal gear 2l being rotated up to a sufficient speed, a centrifugal weight element 68 is mounted on the internal gear member 21 so that a foot-portion 69 of the weight 68 will press forwardly against the iiange-portion 65 of the clutch member 6I and overcome the normal influence of the spring element 63. Thus I have described a distinct clutch unit f of the multi-clutch mechanism which will remain disengaged until areverse of the torque in the transmission initiates rotation of a certain member of the transmission otherwise designed and equipped to stand still. `f

The clutch unit, of which the normally engaged but optionally disengageable clutch element 55 is a component, and the torque reversal centrifugal automatic positive type clutch unit ,f of which the shiftable dentated member 6I is a component, form a system cooperating with the plvotal element, and for completing the driving connections of, one speed ratio of drive effective planetary gear train of a planetary type gearing, such that the respective planetary gear train may be disconnected at will by releasing the friction clutch disk 55 to facilitate the pivotal element 21 of the respective associate planetary gear train reverting to its normally restrained state of rest with resultant automatic disengagement of the positive type centrifugal clutch member 6I from its driving member I6 under urge of the spring 63. Whereupon, the clutch disk 55 may be clutched again without iniiuencing the transmission. One service of the normally engaged clutch unit of which the disk 55 is a component is to superimpose a control of the driving connection over the cooperating positive type centrifugal automatic clutch unit.

For individually connecting the other three clutchI shafts I3, I4 and I5 to the driving member II, respectively in the order named and respectively automatically in response to stepped predetermined speed of rotation attainments by the driving member II, the invention further contemplates three separately engaging master centrifugal automatic clutch units respectively indicated at a, b, and c.

The rearwardly disposed normally spring-engaged clutch unit d completes the flywheel system of four distinct drive connecting clutch units, and due to its mass comprising spacer 53, plates 41 and 48 and disk 55 being normally packed forwardly against the stop I by the urge of th master springs Il, it operates al a back rest for all three of the centrifugal automatic clutch units a, b; c. This relationship of the normally engaged fourth clutch unit d to the three centrifugal automatic clutchl units a, b and c is obtained in the first instance by virtue of the secondary spring 54 resting against the spacer 53 which latter in turn resta against the plate 41 which operates as a first bottom pressure plate to the clutch unit d. And in the second instance by virtue of the first bottom pressure plate 41 to the normally engaged clutch unit d also having a portion 16 operating as a rearwardly disposed bottom pressure plate to the centrifugal automatic clutch unit c.

The first engageable unit of the centrifugal automatic clutch units a, b and c is the unit a. This distinct clutch unit a comprises plate 44 operating as a forwardly disposed bottom pressure plate to the unit a, plate 45 operating as a' pressure plate to engagingly`clutch when thrust forwardly, a driven clutch disk 'II to unit a, rotatable with the first speed clutch shaft I3 and disposed and to be packed between the plates 44 and 45, plate 46 operating as a back plate to unit a and normally urged forwardly to rest against the shoulder 52 by the spring 54, and

master centrifugal weights I2 having feet porpresser plate 45 by which the weight I2 is nor-v mally held in its ineffective state.

The'forwardly first bottom pressure plate 44 of the first engaging' centrifugal automatic clutch unit a has a portion 11 acting as a presser plate to the second engaging centrifugal automatic clutch unit b; The clutch unit b has an individual driven clutch disk I8 rotatable with the second speed clutch shaft I4 and disposed to be clutch-packed between the fiywheel portion 49 and the presser plate portion I1 of the plate 44.

So that the combined bottom pressure plate 44 and presser plate 'I'I will first act as a bottom pressure plate to the first speed clutch unit a without acting as a presser plate to the second speed clutch unit b under initial pressure from the master centrifugal weights 12, the invention contemplates further the provision of dead center linkage e between and normally operative to rigidly space the plate comprising portions 44 and 'II rearwardly away from the fiywheel plate portion 49. By virtue of the linkage e (being normally in a dead center state) the plate 44 is rendered resistant to extreme longitudinal pressure from the rear whereby the centrifugal weights 'I2 may thrust the presser plate 45 and in turn the disk 'II hard against the plate 44 and effect a high torque'l capacity clutching by the first speed unit a of disk 1I without initially effecting any clutching tendency upon the second speedclutch unit b.

The invention further contemplates that the master centrifugal weights 'I2 will operate above `a second speed of rotation attained by their mined interim following clutching of the speed disk 1| under initial pressure from the centrifugal weights 12. To time this interim to correspond to the acceleration interval say between 500 R. P. M., at which it is desired that the engine take ,on theload in first speed, and say 20005 R; P. M., at\which the engine has accelerated the vehicle to sarliiV M.\P. H., respectively.` between desired engagements of first and second speed dlsks1l and 18 under urge from the same centrifugal weights 12, the dead center toggle linkage e may be constructed and equipped as follows: Two links 18 and 88 are linked by pins 8|, 82 and 88 and brackets 88 and 88 to make a dead center toggle in a horizontal (longitudinal) plane between the plate 48 and the flywheel portion 88, when urged radially inward a't the centerpin'82 and to rest against a stop indicated at 88.` So that the center wrist of the linkage e concentrated around the center pin 82 will normally rest against the stop 88 such that the dead'center toggle is normally in eilect to rigidly` space the plates 48 and 88, a centrifugal weight 81 is pivoted to the center wrist connection of the links 18 and 88 by thecenter pin 82, and a spring element, preferably comprising at least two springs 88 and 88 (spaced longitudinally side by side. as illustrated, so that it will be an influence to maintain the weight 81 upright), is provided and interposed radially between the weight 81 and the rim of the flywheel I8. It will be seen that the springs 88 and 88 (of suillcient tension) will operate to restrain the weight 81 from responding to the speed of rotation of the carrying member I8 (flywheel) until the hereinbefore-mentioned second predetermined speed of rotation by the driving member and wheel I8 had been reached, at which time it is desired that the built up pressure of the weights 12 at this comparatively high speed and residing in the plate 88 be released to almost immediately thrust and pack the second speed disk 18 between the portion 11 of the plate M and the flywheel portion 48.

It will be seen that the tension and centrifugal coemcients, respectively, of the springs 88 and 88 and the weights 81 may be of such pre.- determined values that the centrifugal force will counteract the spring tension at' almost any desired speed of rotation by the member I8. And that upon the centrifugal force of the weight 81 overcoming the tension of the springs 88 and 88, the center or wrist pin 82 will be carried radially outward causing the gradual collapse of the dad center-toggle-eiect of links 18 and 88.

Since the master centrifugal weights -12 will first effect the engagement of the first speed clutch disk 1| by'virtue-of the plate M being temporarilyprevented (by the dead center toggle linkage e) from moving .forwardly under the thrust, the centrifugal force of the weights 12 will obviously build up (as the speed increases after the clutching of the disk 1|) in the plate Il. So that, upon the independently centrifugally timed collapse of the linkage e out of its normal dead center toggle state, this built up master centrifugal force in plate 88 will almost immediately effect the clutching `of the second speed clutch disk 18 to the flywheel I8. Thus I have .described in considerable detail the first and second' speed, or flrst two successively'acting centrifugal automatic clutch unitsv ofthe multi-clutch mechanism. I a

It is contemplated that the tension of springs sa and be such that the back plate 4s winv not move rearwardly appreciably under the reassenso nrst" action urge of the foot 12- of the centrifugal weight 12 until a speed of'rotation ofthe member Il has been attainedv which will be an appreciable step higher than that at which the linkage e was centrifugally caused to collapse out of its dead center toggle state and the resultant centrifugal engagement of the second speed clutch disk 18. This' will provide that above a 'third predetermined speed of rotation attained by the member- I8, the-springs 88 or 8| will yield sufficiently to cause a certain backing up of the plate 88 which latter, up until now, has operated exclusively as a back plate taking lthe reaction pressure of the master centrifugal weights 12. 'I'he invention contemplates the use of this aforesaid third-predetermined speed attainment centrifugally accomplished yieldingl of springs 88 and 8| and resultant initial appreciable back- Hwardmovement, of the plate 48 to time, and

2d effect a prim'ing of. a third centrifugal -automatic clutch unit forming a normally non-rotating third speed clutch unit to be initially rotated.

While the present invention contemplates the gagement of oneunit of l clutch mechanism' adapted to one speed ratio of drive, it contemplates also the use of another centrifugal equipped clutching, unit adapted to normally remain at a standstill until excited to initially rotate by a centrifugal means timer. Such normally-still centrifugal-automatic clutch unit ai'- fordingthat the centrifugal weight element may. have a centrifugal coemcient relative to retractive spring tension much higher than ordinarily, Aand by this virtue provide a centrifugal automatic clutch unit which, once excited to rotate up to the speed. of its driving associate member, will develop a high torque centrifugal engagement almost instantly, but with suillcient smoothness (absence of jerk in the resultant change of speed ratio) as to be most satisfactory.

To the end of providing a distinct centrifugal automatic clutch unit in the multi-clutch mechanism such as lastly above described, the present invention contemplates the clutch unit c comprising a -pair of longitudinally relatively expandable driven clutch plates 88 and 8| related relatively expandable (with respect to each other), respectively, plate 88 toward the plate 88 and vplate 8| toward the plate portion 18, wherebythe driven plates 88 and 8| may be clutch packed between the respective associated driving clutch pair of plates 48 and 18. To complete the packing of this distinct clutch unit c to give a distinct driving connection function, the invention v also contemplates a supplemental driven-clutch plate 82 disposing preferably between the driving plate 88 and the adjacent driven clutch plate 88 of the first-mentioned two driven clutch plates 88 and 8|. l

For identification, I term this last-referred-to distinct centrifugal automatic clutch vunit c a free centrifugal clutch, because the centrifugal or speed responsive automatic actuating mechanism of this respective clutch unit is free to standstill while not sufllciently engaged frictionally by some associated member, to cause same indicated at .I to rotate with its associate clutch shaft Il. Preferably this driven clutch plate l2 is equipped with clutch facing on either side as indicated at 04- and 04a. To render the pair of graphite content to render it self lubricating for Y its very limited relative movement bearing duty.

'Ilo the end that the normally rotatably free driven clutch plates l and Il of clutch unit c may normally rest in a state at a minimum distance apart such that it will hold the clutch unit c completely disengaged, the invention contemplates a rearward abutment 01 carried in a fixed position by the hub portion 80 of the plate 92 and a spring 08 compressed between the plate 00 and the abutment 81 so that the supplemental driven plate 02 which is rotatable with the shaft I5 will frictionally-press against the otherwise rotatable free plate 90 suillciently to render a slight brake effect upon the free plate 90 and that a standstill state of the clutch shaft i5 and the supplemental plate l2 will predominate over rotation of associate driving elements thereto, such as driving friction plates 4l and 10. 'I'his brake tension provision upon the distinct centrifugal automatic clutch unit c is designed to maintain the normally free clutch plates 90 and 0I in relationship rotatively exclusively with its associate clutch shaft (individual carrying member) until the speed predetermined timed moment for response of the distinct centrifugal clutch mechanism unit c to the driving member speed and at which moment the plate 40 acting as a presser plate to this particular clutch unit c will have been thrust rearwardly against the tension of springs 54 or 5I into effective drivingengage ment with the supplementary driven clutch plate 02, resulting in turn, in the normally free driven plate 0| being thrust rearwardly into engagement with the plate 10. At this point it will be seen that the normally engaged distinct clutch unity to the centrifugal weights 12 sufficiently to disengage the first speed driven disk 1I of clutch unit a and in turn allow the plate 44 and portion 'I1 thereof to retract rearwardly sufficiently to release the second speed driven clutch disk 18. It is seen therefore that in the multi-clutch mechanism I have provided optional disengagement of a. conventionally (normally) engaged ordinary friction clutch d (respectively designed in this adap.-

tation to function` contributory to connecting a fourth speed) which, besides the desiredprimary results obtained by its individual disengagement, will effect disengagement or prevent engagement of a plurality of other distinct clutch units a, b

and c respectively associated with other speed ratios of power transmission.

Returning to the detail of the clutch unit c.

To the end that the plates 90 and 9| will normally remain longitudinally at a minimum distance apart, the invention contemplates means comprising a stud SS'threaded into an aperture provided in the plate 80, passing through the plate 9| giving a slip ilt of the latter thereon and carrying a spring |00 compressed by suitable means against the plate 9| such that the plates 90 andi will be constantly but yieldingly urge toward each other longitudinally.

To the end that the normally still plates 90 and 9| may be thrust farther apart longitudinally such that the driven plate 9| will be thrust hard against the driving plate 10 and the supplemental driven plate 92 will be thrust hard against the driving plate 46, immediately and with minimum slip even under maximum torque, following the priming frictional engagement of the plate 40 with the driven plate 92, the invention further f contemplates the provision of the following comprising plates 41 and 40 and disk 5B, clutch packed between the spacer ll and stop'element 56 on one side and the springs 5| on the other side, will operate as the bottom pressure element) to the engaging distinct clutch unit comprising the Adriven plate assembly of plates 92, 00 and 0i and the presser plate 40 thereto. Further, at this point it will be seen that suillcient retraction (by actuating the fingers I1) of the bottom pressure plate 48 will operate to'spread the distinct bottom friction plate 10 to the clutch unit c away from .the presser plate 40, to the sameclutch unit c, such that the clutch unit c could not expand longitudinally sufficiently to effect clutching of unit c. The optional disengagement `Vof the fourth speed clutch unit d is seen therefore to control the engageability of the third speed clutch unit c to such an extent that the latter may be either prevented from automatically clutching at its predetermined speed normally controlled time or cause to disengage at any time after it has automa ically engaged. Likewise, it will be seen that the optional disengagement of the fourth speed clutch unit d may be means. Individual centrifugal weights I0| are mounted by feet portions |02 wedged operatively between the normally still plates 90 and 9| and designed to thrust these plates apart immediately at a high pressure coefficient relative to comparatively low speed of rotation. To obtain this high pressure coefficient from the centrifugal weights I 0| at low speed of rotation such that maximum torque capacity engagement of the clutch unit c will result immediately from low pressure prlming-to-rotate engagement of the presser plate 46 with the normally still assembly 'of driven plates 92, 90 and 9|, advantage is taken of the virtue of this assembly of driven clutch plates of clutch unit c normally standing still until engaged by the plate 46. The requirement hence of the retractive or clutch disengaging spring element |00 distinct to clutch unit c, to straighten the centrifugal weights IOI into their normal non-speed responsive positions and to retract the plates 90 and 9| into their aforementioned minimum positions apart longitudinally while at rest would be slight. This requires that the centrifugal weights 10| be of unusually high centrifugal value relative to their retractive spring element |00. It also requires that the rate of centrifugal acceleration distinct to effecting maximum torque engagement of the clutch unit c will be unusually high.

suillcient to allow retraction of the back plate 40 75 So that the relative-movement end of the spring 98 will not be required to work against the respective abutment of the same, preferably the abutment 91 is made to consist of at least two parts for relative rotative movement therebetween. A suitable bearing provision of these two parts would be to provide the outer part of steel and the Other part, being that between the outer assavso 7 part and the spring end, of graphite impregnated bronze.

It will be noted that the design of gearing illustrated, exemplary of that which would coordinate advantageously with the multi-clutch mechanism, and the latter while comprising five distinct clutching units giving four speed ratios of driving connections and affording directly optional declutching of foul` of the five distinct clutching units and facilitating indirectly optional declutching of the fifth distinct clutching (positive type) unit, still gives a mechanism the entirety of which gearing, shafting and clutch mechanism may rotate as a unit when in the highest speed ratio of drive state of connection.

Operation of the invention follows:

With the engine (driving member I and II) idling under, for example, 500 R. P. M., the pressure of the springs 88 and 89 is greater than the centrifugal force of the weights 81 thus establishing a dead center relationship of the toggle linkage e and resulting in the plate 44 and portion 11 being locked longitudinally with, but at a maximum distance away from, the bottom pressure portion 48 of the iiywheel I0. This renders the second speed clutch unit b open; and with the engine (driving member I Il and II) idling under 500 R. P. M., the valueof the retractive springs 18 is greater than the centrifugal force of the weights 12, resulting in the plate 45 being held at a maximum distance from the plate 44. This renders the first speed clutch unit dopen; and with the engine (driving member I0 and II) idling under 500 R. P..M., the value of the springs 54 and 5I is greater than the reaction force of 88 the centrifugal weights 12 against their "back plate 48, thuspreventing a driving engagement lof the plate 48 withl the plate 82. This leaves the free third speed centrifugal automatic clutch unit c unmolested; and, by virtue of the driving clutch units a, b and c remaining disengaged, the planetary gearing including the internal gear 21 may remain at rest. This assures that the positive type centrifugal automatic clutch unit f will' stand disengaged. The single normally engaged clutch unit being the fourth speed completing t clutch unit d. Therefore, clutch shafts I3, I4

and I5 stand still while the driving member I 0 idles under 500 R. P. M., and the clutch shaft I8 rotates (through the medium of the engaged clutch unit d) with the driving member I0.

Assuming a desired performance of starting the vehicle (load on driven shaft I2) from a standstill and accelerating through different speeds to ultimately reach a top speed ratio, the engine (driving member I0 and II) is accelerated. Passing above the 500 R. P. M. (exemplary first predetermined speed of driving member) the weights 12 overcome the springs 15 and thrust the plate forwardly. The toggle e still prevents the plate 44 from backing away from any thrust from the rear. Hence the first speed driven clutch disk 1I becomes automatically clutch packed between the plates 44 and 45 by the first predetermined speed attainment of the driving member I0. Thus resultant connection of the clutch shaft I 3 to rotate with the engine shaft II promotes the one-way drive of the first speed sun gear 22 through the medium of the roller clutch members 42. Subsequently, gears I9 and 28 back the torque of this drive up against the roller brake members 81 in the stationary annulus Stand cause the planet carrier I1 and at the lowest ratio of speed relative to that of the drivingr member II.

For example. at a vehicle speed of 10 M. P. H. under drive of this first gear (which latter if of 8 3 to 1 ratio would iind the engine rotating at say 10 trifugal force of the weights 12, built up in the packed plates 45, 1I and 44 between the 500 and 1500 R. P. M. attained by the driving member II, to be gradually but quickly exerted in the way ofl thrusting the portion 11 of the plate 44 1| forwardly as the linkage e gave way under the somewhat gradual yielding of the springs 88 and 88. This resulting in the second speed driven disk 18 becoming packed between the portion 49 of the flywheel I0 and the portion 11 of the plate lo 44. The second speed clutch shaft I4 now rotating with the driving member I I supplants the first speed drive of the sun gear 22 with the second speed drive ofy the sun gear 2I. The sun gear 22 overrunning its clutch shaft I3, the torque of this second speed drive backing through gears I8 and 21 against the roller brake members and annulus 81 and 83 with consequent driving of the planet carrier I1 and integral driven shaft I2 at second gear reduced speed relative to that of the driving member I I.

40 would have overcome either the springs 54 or the springs 5I, or both, sufciently to have incurred the centrifugal-means-forcing of the reaction plate 48 to the centrifugal weights 12 rearwardly (asa presser plate) into engagement with the driven clutch plate 82. By this engagement, the centrifugally actuated plate 48 becomes an exciter to initiate rotation of the normally still assembly of driven plates 92, 88 and SI. Since this assembly (clutch c) has its own master speed responsive actuating means IOI and this assembly (clutch c) is not rotated until the driving member thereof has attained a speed of substantially 2000 R. P. M. (corresponding to 20 M. P. H. vehicle speed attainment in second gear); and since the assembly of driven clutch elements of this clutch c and their individual speed responsive means IOI will be urged by engagement by the driving clutch plate 46 to accelerate at once from a standstill to the aforesaid 2000 R. P. M. speed of the priming engaging plate 48. it will be obvious that the third speed clutch unit c will come into play under a centrifugal force acceleration such that the slip will be almost nil. The inertia of the assembly of driven plates 92, 90 and 9i and that of this assemblys .individual centrifugal weights I 0I will operate advantageously to retard the acceleration of this driven mass slightly, and tend to promote an instant of slip calculated to make the engagement of this clutch unit c sufficiently gradual to obviate a jerk in its action of stepping up the drive from second to third ratios.

By virtue of the planetary gear unit comprising gears 21, 25 land 28 remaining inactive (standthe integral driven shaft I2 to rotate forwardly 75 ing still as a unit) while the transmission is operating in first or second gear, respectively. under drive of either shaft I2 or shaft il, which inactive state of gears 21, 25 and 26 is the result of the distinct planet carrier 24 thereto being integral with the pivotal element 23 of either the first or second speed gear trains hereinbefore identified, the third speed clutch shaft i5 and the driven assembly of plates 92, 9|) and 9| and distinct centrifugal weights IUI all are caused to stand still until excited to rotate as hereinbefore stated by priming engagement of the driving plate 4G therewith.

The invention contemplates the further advantage from the novel multi-clutch provision, and in connection with a gearing such as the exemplary design shown, in that the third speed ratio of drive incurred by the accumulative engagement of the novel quick-acting centrifugal automatic clutch c supplementing the previously engaged clutch unit b, with resultant taking of the load (at third speed ratio from the second speed ratio) by the two planetary gear trains in series, will have the eiIect of placing but one half the load of the third speed on each of the two clutch units b and c. The operation of the two planetary gear trains in series to give the third speed ratio is the result of the engaged clutch unit c causing the sun gear 28 to initiate its drive of the planet gears 25 which latter, running in the internal gear 21 respectively held from rotating backwards by the roller brake members 34 and stationary annulus 32, impels the planet carrier 24 thereto to rotate at reduced speed in a forwardly direction and carry the internal gear 23 of the second planetary gear train with it. Whereupon, the normal (second speed ratio) drive by the previously engaged clutch unit b and shaft I4 and sun gear 2| and planet gears i8 to the planet carrier i1, is stepped up to that of a third speed ratio of speed reducing drive of the driven shaft I2. In contemplating this dual clutch and dual planetary gear train drive coordinating to give a change of speed ratio drive, especially a third speed ratio to supplant a second speed ratio, it is calculated that the high engine torque developed by the time such a speed change was advantageous in the process of load acceleration, would advantageously be served by two individually centrifugally served automatic clutches, such as the coordinate of a plurality of planetary gear trains in series to give a certain speed ratio of drive would cooperate with.

On the same premise of high engine torque prevailing at comparatively high vehicle speed attainments, the present invention contemplates and provides for bringing the fourth (t`p) speed ratio' of drive into effect by the engagement of a distinct clutch unit co-related with preceding clutches engaged to the end that the load of the fourth speed ratio may be carried also by a multiple of individually energized clutch units. To this end, and also that the third speed may be maintained for acceleration to any desired vehicle speed attainment at the will of the driver, the invention contemplates the provision of the positive type centrifugal automatic clutch unit f which may be coordinated with a pivotal element of an internal gear train such that a torque-reversal control may be provided by the driver: in novel clutch co-working combination with either the normally engaged but optionally disengageable clutch unit d; whereby the positive centrifugal clutch l may be optionally facilitated to disengage at the will of the driver,

or in novel coordination with other of the individually energized clutch units of the multiclutch mechanism such that it may be harnessed to the planetary gear trains in series whereby the load may be divided between the plurality of clutch units including the positive type unit l.

Therefore, at any vehicle speed attainment above, for example, 20 M. P. H. (at which the exemplary transmission will automatically normally come into play at third speed ratio drive), tive diriver may, by momentarily decelerating the engine, cause the fourth speed (direct drive by the exemplary transmission gearing) to come into play and supplant the third speed ratio. In detail, by momentarily decelerating the engine, the sun gears 2|, 22 and 26 all being operatively connected to the driving member (engine shaft) I l, will have the immediate effect of accelerating the planet gears I9 and 25, respectively, to run around their decelerating sun gears 2| and 26, thus accelerating their respective internal gears 23 and 21 until the centrifugal weight element 68 carried by the internal gear 21 attains suilicient force and until the speeds of the clutch shaft I8 and internal gear 21 are substantially synchronous, at which moment the weight element 68 will actuate the positive clutch member 6| forwardly into clutch tooth mesh with the shaft I6. 'I'he entire exemplary planetary type gearing and multi-clutch assembly thus becomes locked into a rotating unity, giving a direct drive (fourth) positive connection between the driving and driven members and 2.

It is a matter of common appreciation that ability, once in top speed gear, to easily revert the transmission to the next-in-ratio lower speed gear, would be very advantageous. To this end, the provision of the optionally disengageable friction type clutch unit d suffices. For at will, after the positive type centrifugal automatic clutch f has become engaged, the driver may momentarily cause the clutch unit d to disengage, thus loosening the shaft I6 and connected internal gear 21 from the driving member il, whereby the internal gear 21 may decelerate below a speed of rotation at which the centrifugal weight element 68 will be overcome by the springs 63, with the result that the clutch member 6| will be shifted rearwardly out of engagement with the shaft I6. Whereupon, the clutch unit d may be allowed to engage again. The exemplary planetary gearing being thus reverted from one speed ratio downward to another relatively lower speed ratio.

Thus it will be seen that I have provided a novel, rugged and useful multi-clutch mechanism particularly advantageous for use in motor vehicles and capable of improved performance in connection with rendering automatic speed change control over multi-speed power transmissions.

It will be understood that various changes may be made without departing from the spirit of the invention as defined in the appending claims. I do not want to be limited to the examples and details described in the specification or shown in the drawing, as many variations will occur to those skilled in the art.

I claim:

1. In clutch mechanism, a revolvable clutch carrying power transmitting member, a bottom friction face portion of said carrying member, a presser friction clutch member rotatable with said carrying member, a coaxial engageable friction element between said bottom and presser members, linkage carried by said carrying member, arranged between said bottom and presser members and adjustable therebetween in substantially a dead center toggle effect for firmly spacing said presser member away from said bottom member whereby said engageab1e.friction element will be free to turn relative to said bottom and presser members, resilient means tending to adjust said linkage in said dead center toggle effect, said linkage having proportions and operable constituency whereby centrifugal force when said carrying member is rotated sufficiently will concentrate at a point operable to overcome the influence of said resilient means and centrifugally actuate said linkage out of said dead center toggle effect i. e., a state of collapse permitting said presser member to be actuated toward said bottom member to-accomplish packing of said engageable element therebetween, and means including main centrlfugally operable means carried in rotation with said carrying member operable to initiate urge upon said presser member beginning in response to comparatively slow speed rotation of said carrying member and to gradually increase the force of said urge in accordance with increasing speed of rotation of saidcarrying member such that when said collapse of said linkage from said dead center effect takes place a sunicient main centrlfugally actuating force will be present in said presser member to accomplish substantially instant packing of said engageable friction element under torque at least so as to preclude an appreciable slip period between the frictionally-engaging elements, said linkage of itself forming a subcentrifugally operable means to time a permissible centrifugally actuated clutch engagement so that main centrlfugally operable means to that end will not gradually transmit response to gradually increasing speed of rotation to the named frictionally-engaging members.

2. The mechanism described in claim 1, together with a primary presser member rotatable with said carrying member and directly acted upon by said main centrlfugally operable means with retractive means including springs for holding said primary presser member from yielding appreciably to urge from said main centrlfugally operable means until a predetermined speed of said comparatively low speed of said carrying member has been attained, and a first engageable friction element to turn relative to both said carrying member and the first-mentioned engageable friction element and disposed between said first-mentioned presser member and said primary presser member, wherein said first-mentioned presser member first operably constitutes a bottom friction member to said first engageable friction element, and wherein an engaged relation of said primary presser member and said first engageable friction element and said first operable bottom friction member under pressure from said main centrlfugally operable means constitutes a presser body for subsequently packing said first-mentioned engageable friction element against said bottom friction face when said collapse of said linkage occurs.

3. In a clutch mechanism, two friction clutch members to rotate together normally to be spaced apart sufficiently to accommodate an engageable friction element being disposed freely rotatable relative therebetween and at least one of' said two members adapted to be urged to move toward the other of said two members to lessen l-one disposed between said their normal spacing whereby an engageable friction element therebetween would become clutch packed, dead center toggle linkage for adjustment in a dead center alignment when so adjusted forming means for effecting said normal spacing of said two members including a wrist of said linkage mounted on one and another wrist of said linkage mounted on the other of said two members and an intermediate wrist, means including a spring element concentrating an urge upon said intermediate wrist forming means for automatically adjusting said linkage in dead center alignment, and suflicient weight suspended around said intermediate Wrist operable to concentrate suilicient centrifugal force therearound when said two members have attained a predetermined speed of rotation to overcome the influence of said springs and actuate said intermediate wrist out of said dead center alignment whereby a lessening of said normal spacing of said two members will be permitted, and means for. and adapted to havesufllcient force at that time to immediately accomplish, said lessening of said normal spacing of said two members to a required degree for non-slip clutch packing of an engageable friction clutch element therebetween.

4. In a centrifugal friction clutch mechanism, the combination of a system of centrifugally operable means for engaging the clutch, a timer system of centrifugally operable means for holding the clutch elements against being actuated toward engagement by-said engaging centrifugal system until the latter has passed through a sufficient increasing speed of carried rotation above that at which its centrifugal coefllcient would overbalance its retractive spring influence and has thereby accumulated sufilcient centrifugal pressure to substantially immediately hold the clutch against gagement is initiated, -a system of retractive springs for opposing the clutch engaging centrifugal action having a co-efllcient to that end only effective to a peak idling speed of rotation, and a system of retractive springs opposing the timer system of centrifugal action having a coeicient to that end effective to a considerably higher speed of rotation being that at which the clutch engaging centrifugal means will have accumulated said suillcient pressure to substantially immediately engage and hold the clutch.

5. In a centrifugal friction clutch, a bottom pressure friction member, a back plate, a presser plate adjacent said back plate and an intermediate plate between said bottom member and said presser plate. all rotatable together forming a multi-clutching coordination; two coaxial engageable friction clutch elements independently revolvable with respect to each other and to the namedelements of said clutching coordination presser and intermediate plates the other between said intermediate plate and said bottom member; retractive means including springs urging said presser plate `to ward said back plate, clutch actuating centrlfua gally operable means operatively between said presser and back plates for actuating said presser plate away from said back plate when a first predetermined speed of rotation has been attained by said clutching coordination; retractive means operatively between said intermediate plate and said bottom member including springs effective to prevent movement of said intermediate plate towards said bottom member until a second, and appreciably stepped speed of rotation over said slip under the torque once en first predetermined speed, has been attained by said clutch coordinationi and means including masses acting against the springs respectively of the retractive means positioned aforesaid between said intermediate plate and said bottom member, forming masses centrifugally operable when said second predetermined speed of rotation has been reached to cause collapse of the respective retractive means thereby to release said intermediate plate movable towards said bottom member, an engaged unity comprising said presser plate and said intermediate plate clutching the interposed one of said engageable friction elements therebetween under pressure from said clutch actuating centrifugally operable means during the interim between said nrst and said second predetermined speed of rotation attainments forming an accumulatively built up pressure mass for movement towards said bottom member when said retractive means therebetween is collapsed centrifugally and for consequent clutching of the other of said engageable friction elements therebetween.

6. In a centrifugal clutch mechanism, a two stage engaging clutch unit comprising two independently revolvable friction clutch elements, a revolvable unit oi' clutching elements spacing said two engageable elements for spaced engagement with respect to stepped predetermined speeds of rotation being attained by said clutching unit of elements, a master system of centrifugally operable means for energizing engagement of the first of said two engageable elements when the first of said stepped predetermined speed of rotation has been attained and for latter energizing engagement of the other of said two engageable elements when the second of said stepped predetermined speeds of rotation has been attained, means including springs acting thereon for preventing response of the clutching elements movably towards accomplishing engagement of the second of said two engageable elements under urge from said master centrifugally operable means to that end following their effected engagement of the first of said two engageable elements, and independently centrifugally operable means operable when the second of said stepped predetermined speeds of rotation has been reached to release said preventing means suddenly for the until then restrained pressure of said master system of centrifugally operable means operating through their first effected clutching function to suddenly accomplish full torque holding clutch packing ofthe second of said two engageable elements.

7. In a friction clutch mechanism, the combination of a main spring and centrifugal weight coordination carried by the clutching division of the mechanism in which the spring tension and centrifugal forces balance when the carrying clutching division has attained a comparatively low first predetermined speed of rotation and wherein if not restrained therebeyond the centrifugal forces would tend to actuate the clutching division towards engagement such that clutch engagement would initially begin and progress under gradually increasing pressure in accordance with gradually increasing speed of rotation by said clutching divisionand accordingly allow `a gradually diminishing clutch slip period under torque; and a coordination of other spring and centrifugal weight means spring operable, until a second and appreciably greater predetermined speed of rotation is attained by said clutching division of the mechanism, to prevent said clutch engagement, under centrifugal urge from said main coordination of spring and centrifugal weights, from initially beginning and progressing under gradually increasing pressure in accordance with gradually increasing speed as aforesaid, and centrifugally operable when said greater predetermined speed of rotation is attained to release the clutching elements for substantially instantaneous engagement by the centrifugal forces of said main coordination up to a clutch holding coefiicient under torque.

8. In a friction clutch mechanism, a multiclutching embodiment comprising, in combination, a rst unit of engageable driving and driven friction clutch elements and a second unit of engageable driving and driven friction clutch elements; first centrifugally operable means for gradually exerting increasing pressure for a consequent gradually increasing clutching coefficient in said first unit only in accordance with gradually increasing speed of rotation by the clutching embodiment from a comparatively low rst predetermined speed of rotation up to a speed at which the centrifugal force will be sufiicient to hold said first unit non-slip under full torque: a first system of springs yielding to said centrifugally operable means at said comparatively low rst predetermined speed of rotation, means including a second system of springs for holding said second unit of engageable clutch elements open and operable in their open state as a nonyielding bottom friction element to said first unit while the latter are being gradually centrifugally engaged with increasing speed of rotation upwards from said first attained predetermined speed: and second centrifugally operable means, for overcoming said second system of springs thereby to loosen said second unit of engageable clutch elements actuable to be engaged by pressure from said first centrifugally operable means adapted to reach said second unit of engageable clutch elements through the engaged state of said first unit, operable when a second predetermined speed of rotation has been attained and at which said first centrifugally operable means will be exerting a sunicient pressure in the engaged body of said first clutching unit to substantially instantaneously effect engagement of said second unit under full torque without appreciable slip period in said second clutch unit.

9. Mechanism as in claim 8 and wherein said second centrifugally operable means, following its operation loosening said second unit of clutch elements actuatable to be engaged under pressure from said first centrifugally operable means, with further increasing speed of rotation tends to energize engagement of said second unit supplementively over that tendency on the part of said first centrifugally operable means.l

10. In a clutch mechanism, the combination .with a driving member and a plurality of concentric driven members coaxial with said driving member, of an individual engageable friction clutch element rotatable with each of said concentric members, driving clutch elements rotatable with said' driving member and spacing said engageable elements respectively that are certain of said separate clutching umts from their respective spring means held disengaged states whereby they may be actuated into engagement by said first-named centrifugally operable means.

11. Mechanism as in claim 10 and wherein said other centrifugally' operable means comprises linkage for actuation into a dead center toggle effect by the spring means associated with the respective of the multiple of separate clutching units with which said other centrifugally operable means are also associated by said dead center toggle preventing engagement of the respective separate clutching unit, said linkage centrifugally operable to overcome said springs of the respective separate clutching unit and collapse out of said dead center effect thereby to permit said first-named centrifugally operable means operating to engage the respective separate clutching unit.

12. In a friction clutch mechanism, the combination of two clutching units of frictionallyengaging elements having first centrifugally operable means for energizing engagement of both and having combined spring and second centrifugally operable mechanism for spring pre- 13. In a multi-clutch mechanism which includes two units of frictionally-engaging clutch elements respectively adapted for separate and spaced engagement with respect to an appreciable dinerential between two prodetermined speeds oi? rotation being attained, the combination of individual spring actuated means for disengaging each of said two units one up to a first predetermined speed of rotation being attained in the mechanism the other up to an appreciably greater second predetermined speed of rotation being attained in the"mechanism, centrifugally operable means solely for actuating clutch engagement arranged operable rst to effect engagement of said one of said two clutch units when said first predetermined speed of rotation has been attained and adapted to occumulatively effect engagement of said other of said two clutch units when said second predetermined speed of rotation has been attained, and

other centrifugally operable means associatedv solely with said other of said two clutch units and therewith forming means solely for actuating said spring actuated means thereof out of its position, in which 1t effected disengagement of the respective clutch unit, when said second predetermined speed of rotation has been attained wherebysaid centrifugally operable means aforesaid solely for actuating clutch engagement may thereupon actuate said other clutch into engagement accumulatively over engagement of said one clutch unit.

14. A centrifugally operated friction clutch unit having a first system of centrifugally operable weights carried by one of its driving and driven members for urging engagement upon has been attained,

the clutch through a considerable range of rotation speed, having means including springs spacing the clutching elements apart unmovable by said urge from said first centrifugal weights, and having a second system of centrifugally operable weights operable to overpower said springs and cancel their spacing influence between the clutching elements when a sufficiently high speed of rotation has been reached at which said first system of weights will have attained sufficient centrifugal force to substantially instantaneously accomplish the clutch engagement when under full torque without appreciable'clutch slip.

15. Mechanism as in claim 14 and wherein said second system of centrifugally operable weights constitute secondary means centrifugally operable to energize engagement of the same clutching unit supplementively to-the influence of said first system of centrifugally operable weights to the same end operating thereon but only after overpowering said springs at said sufficiently high speed of rotation for said first systemof weights to substantially simultaneously accomplish full torque holding engagement of said clutch unit.

16. A centrifugally engaged friction clutch unit having a first system of centrifugally operable weights for urging engagement upon said clutch unit from a low speed of rotation upward throughout the rotation range and an independently operating coordination of spring and second centrifugally operable weights forming means for preventing responsive movements in said clutch unit towards engagement under said urge of said first system of weights until an appreciably greater speed of rotation has been attained whereupon said second centrifugally operable weights form means operable both to overcome the inuence of said springs thereby to release the elements of said clutch unit to respond to said urge from said first system of weights and to supplement said urge with the urge of their own centrifugal forces to thecommon end of energizing engagement of said clutch unit.

17. In a centrifugally operated friction clutch mechanism, a given clutching unit having two independently operating systems of centrifugally operable weights for energizing engagement of the respective clutching unit one provided with resilient retractive means allowing the one system of weights to begin their clutch engaging actuating urge upon the respective clutching unit at a predetermined low speed of rotation the other provided with resilient means allowing it to begin its clutch engaging actuating urge upon the respective clutching unit only when an appreciably greater predetermined speed of rotation the latter of the two systems of weights forming mechanism actuated by its own, resilient retractive means into a position firmly blocking the clutching elements apart so ytheycan not yield to urge from said one system of weights until said other system of weightshave responded to speed at the point of saidv appreciably higher predetermined speed of rotation being reached.

18. In a centrifugally operated friction clutch mechanism, centrifugal weights normally positioned spacing the engaging elements of the clutch apart in an open clutch state, resilient means capable up to a predetermined speed of rotation to hold said weights in said spacing position, and other centrifugal weights adapted to have sufficient centrifugal force when said predetermined speed of rotation is reached to substantially instantaneously actuate said clutching elements up to a full torque holding clutch gripping ooeiliciency thus to obviate a prolonged slip period in connection with friction clutch engagement under torque.

19. In a centrifugally operated friction clutch having a bottom friction plate and a presser friction plate the latter adapted to be moved axially towards said bottom plate to effect clutching function within the clutch, the combination of a pushing centrifugally operable system of weights operatively behind said presser plate for thrusting same towards said bottom plate, and a system of pulling centrifugally operable weights operatively interconnecting said bottom and presser plates for pulling the latter towards said bottom plate.

20. The mechanism described in claim 19, together with a separate system of resilient re- `tractive means for overcoming the pulling-action of said system of weights, aforesaid having that character of action, until a predetermined speed of rotation has been attained. and a separate system of resilient retractive means for overcoming the pushing action of said system of weights, aforesaid having that character of action, until a predetermined speed of rotation has been attained.

21. The mechanism claimed in claim 19, wherein said pushing system of weights are operable to engage one clutching unit and thereupon urge the engagement of a second clutching unit, and wherein said pulling system of weights are operable to release the elements of the second clutching unit to yield engagingly to said urge from said pushing system of weights, said pulling system of weights operable thereafter to supplement the urge by said pushing system of weights to the common end of energizing engagement of the second clutching unit.

22. In a centrifugally operated friction clutch mechanism, between a driving power transmitting member and a coaxial driven power transmitting mechanism, the combination of a contracting full complemented centrifugally operable clutching unit carried in rotation with said driving member, an expanding full complemented centrifugally operable clutching unit mounted rotatable independently of said driving member and disposed to be clutch packed between the clutching elements of said contracting clutching unit, and a friction clutch element mounted in an engageable position to turn with said driven member disposed as an intermediary between elements of both named clutching umts so as to be clutch packed under centrifugal pressure from both named centrifugally operable clutching units.

23. In a centrifugally operated friction clutch mechanism, between a driving power transmitting member and a coaxial driven power transmitting member, a clutching unit for connecting said driving and driven members to rotate together comprising, in combination, a priming centrifugally operable clutching element carried in rotation with said driving member and having its own actuating centrifugal weights, a booster centrifugally operable clutching element mounted rotatable independently of said driving member and having its own actuating centrifugal weights, an engageable friction clutch element mounted in connection to turn with said driven member, said priming centrifugally operable clutching unit forming a clutching unit for exciting said booster centrifugally operable clutching unit to rotate up to the speed of said driving member, said booster centrifugally operable clutching unit forming a secondary centrifugally actuating clutching unit to supplement the pressure of centrifugal forces operating in said priming clutching unit, and said priming and said booster centrifugally operable clutching units when both operating forming double pressure centrifugal energizing elements for clutch packing said engageable frictionclutch element to rotate with said driving member.

24. In a centrifugally operated friction clutch mechanism between a driving power transmitting member and a driven power transmitting member, the combination of an exciter driving clutching system rotatable with said driving member and having its own centrifugal actuating means responsive to the speed of said driving member, and an excitable driven clutching system mounted rotatable independently of, but associated with, said exciter clutching system and having its own centrifugal actuating means carried in rotation therewith, the combined actions of said exciter and excitable clutching systems forming a clutch unit under double centrifugally operable systems for coupling said driven member to rotate with said driving member.

25. In multi-clutch mechanism positioned at different interruptions in a circuit of connections for transmitting drive when closed, the combination of a positive clutch unit for connecting one pair of members of said circuit engageable only when'its two members are operating in substantial synchronism and having centrifugally operated means for moving one of the clutch members into engaged position: and a friction clutch unit for connecting another pair of members of said circuit, having resilient means normally but yieldingly engaging same and having means for its disengagement at will forming flexible coupling means in said circuit for opening and closing the latter without molesting said positive centrifugally engaged clutch unit.

26. Multi-clutch mechanism, differentially associated with change speed power transmitting mechanism for automatically changing the latters driving ratio between two of its members from one speed to a faster speed, comprising the combination of a centrifugally operable friction clutch unit for establishing said one driving ratio; a positive clutch unit for establishing said faster speed engageable only when its two positive clutch members are operating substantially in synchronism and centrifugally operable means for actuating one of the two positive clutch members into engaged position, and a friction clutch in series with said centrifugally actuatable positive clutch having solely resilient means tending to engage same and having means for forcing its disengagement at will forming a flexible coupling in tandem with the coupling establishable by said centrifugally actuatable positive clutch whereby the speed established by the latter may be abnormally disestablished at will without molesting said positive clutch and without immobilizing the driving connections of said faster speed.

27. In a clutch mechanism having driving and driven members, a restraining mechanism normally adapted to hold said clutch in an open state by preventing movement of one of said members toward the other of said members, means operable under certain conditions to render said restraining mechanism ineffective to hold said clutch in an open state, means adapted under certain conditions to urge at least one of said clutch members toward the other of said clutch members, and at least one of said certain conditions being fulfllled when one of said clutch members exceeds a predetermined speed of rotation.

28. In a clutch mechanism having driving and driven members, a restraining mechanism normally adapted to hold said clutch in an open state by preventing movement; of one of said members toward the other of said members, speed responsive means operable to render said restraining mechanism ineiective to hold said clutch in an open state, speed responsive mechanism acting to urge at least one of said clutch members toward the other of said clutch members, the latter meansV adapted to place the clutch member it acts upon under considerable force tending to move said clutch members together before the first said speed responsive means renders said restraining mechanism ineffective whereby engagement of said clutch is substantially instantaneous to bring the clutch elements to a substantially full torque holding capacity to prevent prolonged slip periods in connection with the engagement of said clutch under torque.

29. In a multi-clutch mechanism adapted to be positioned in series in a circuit for transmitting drive when all of the units of said clutch are engaged, the combination comprising a positive clutch unit for connecting one pair of members of said circuit and engageable only when the said pair of members are operating in substantial synchronism, speed responsive means to engage said clutch, a slippable clutch unit for connecting another pair of members of said circuit for forming flexible coupling means in said circuit for opening and closing the latter without immobilizing the driving connection established by the positive clutch.

30. A multi-coupling mechanism for use in a circuit including parallel power flow lanes comprising a plurality of coupling mechanisms to be positioned at dierent interruptions in said circuit for transmitting drive through said circuit when both of said couplings are engaged, one of said coupling mechanisms comprising a positive clutch unit for connecting one pair of members of said circuit and engageable only when its two members are operating in substantial synchronism, means to engage said clutch, another of said coupling mechanisms comprising a slippable coupling unit for connecting another pair of members of said circuit theneby forming flexible coupling means in said circuit for opening and closing the latter without immobilizing the driving connection established by the positive clutch.

3l. In a clutch mechanism, a driving member, a plurality of driven members, power actuated means to cause relative engaging movement between friction elements on said driving member and similar elements on said driven members to cause said driving member to drive all of said driven members, and means operable independently of the power actuated means selectively to prevent or permit relative engaging movement between some of the friction elements on said driving member and the similar elements on at least one of said driven members while permitting relative engaging movement between the other friction elements on said driving and driven members, whereby said power actuated means can be used to pack the whole clutch mechanism or only a portion thereof.

32. In a multiple clutch, a pair of clutch driven plates, a pair of clutch driving plates positioned between the driven plates, power operated means to force said driving plates apart for engagement with both of said driven plates, and means to prevent engaging movement of one of said driving plates until after the other of said driving plates has been packed against its driven plate.

EVERETT R. BURTNEI'I.

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