US2325596A - Disk brake - Google Patents

Description

Aug. 3, 1943. EgR. EVANS 2 DISK BRAKE Filed July 25, 1938 5 Sheets-Sheet l 'Jmnentor E. B. EVANS B ,h Q a (Ittorneg 3 I E. R EVANS 2,325,596

DISK BRAKE Filed July 25, 1958 5 Sheets-Sheet .2

3nnentor ER EVANS r (Ittomeg 1943- .E. R. EVANS 2,325,596

Ennentor E. R. EVANS F xlttorngga 5 Shets-Sheet 4 DISK BRAKE E, R. EVANS Filed July 25 Aug. 3, 1943.

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E, R, VANS DISK BRAKE Fii'd' July 2 1938 5 heet '5 17 a d 55 I I '22! I I 6 5' w. I

66 W16, nu 17 2:: I ll I r E v 17. 70 I 2 UNITED STATES nlsx mu m 1:. Ivan. Mich. museum July ss, ms, Serial is... cause (01. Isa-m as use.

and partie- An object oi the invention is to securea flexible This invention relates to brakes ularly disk brakes.

7 disk to a wheel or other rotating member, to arrange a pair oi substantially rigid non-rotative plates at opposite sides oi such disk, and to provide mechanism ior clamping the plates against the disk to app y selective braking pressures, flexibility oi the disk assuring its iull coniormity to the plates.

Another object is to adapt such plates ior a limited floating movement along the brake axis, so that they may adjust themselves under all conditions to coact'to best advantage withthe flexible disk.

A iurther object is to mount a pressure-applying lever mechanism entirely on said plates, and to adapt one oi the plates to take the fulcrum reaction in applying leverage to the other, where- I by the forces oppositely applied to the disk are iully equalised.

Other objects are to achiev a much more rapid dissipation oi heat than is permitted by brakes nowinuse,andto sodesignsaiddiskand plates that efliciency oi the brake will not be materially diminished by distortion incident to rapid heat generation due to severe braking.

A further object is to provide a disk brake sioirotatiomapproximatelyonth'elineHoi Fig.1, the hubbeingagalnomitted.

1"lg.4isahoriaontal,sectionalviewtakenon the line 4-4 oi Fig. 8, primarily showing an arrangement oi secondary leversior actuating the brake.

Pig. 5 is a radial, horizontal, sectional view oi thebrake,takenonthelinelloil'1g.8.

Fig. 8 is a view showingthe mounting oi one oi a pairfoi' primary levers, and is, in part, a section on 0-4 oi Fig. 8.

' -Fig. 'l is across sectional view, taken on the line 1-1 oi Fig. 6, showing an adjustment means ior said primary lever.

Fig. 1A is a cross sectional view, taken on the line IA-IA oi Fig. 6, showing a provision ior limiting adjustment.

Fig.8isatopplanviewoithebrakeshowing how a conduit ior an actuating cable is extended from the brake to the irame oi a vehicle equipped with the brake.

Fig. 9 is a radial, horizontalsectional view oi a slightly modified construction oi the brake.

Fig. 10 is a view similar to Fig. 4 butshowing hydraulic actuating means ior the secondary levers.

.l 'lg. 11 is a atic view oi a thrust- 'transm'itting mounting ior a brake-actuating iording simple and highly accurate manual adjustments to estabiishproper clearance between the motion-applying and iriction-receiving elements under non-braking conditions, and to provide ior automatically establishing such a clearance, in case a mechanic iails to complete such an. adjustment. i

A iurther object is to establish a highly eiiective anti-friction relation between a non-revolublesliding plate or disk member oi a brake and an anchorage means for such member, whereby th torque-induced tendency toward heavy iriction is largely eliminated in enga in or disen-' gaging such member with a companion revoluble member.

These and various other objects are attained by the construction hereinafter described and illustrated in the accompanying drawings, wherein:

cable, an alternative to the conduit mounting shown in other figures.

, In these views, the reierence character I designates a wheel body integrally formed with a huh I and driven through any ordinary connection (not'shown) irom a live axle I. The latter prolects in the usual manner irom a tubular axle housing I, terminally formed with the customary annular end plate or flange I ior brakemounting purposes. Rigidly secured to the outer portion oi thebody I is a ring 0 ior carrying a tire-mounting rim (not shown), the securing means being a plurality of studs 1 having heads .l engaging the inner iace oi the body I, and

Fig. 1 is -a diametrical, vertical, sectional view I oi the improved brake, as applied to a vehicle wheel. a

, Fig. 2 is a sectional view oi the same, taken in a plane oi rotation and on the line 22 of Fig.1,

omitting the wheel hub. Y

Pig. 3 is a sectional view taken in another planecarrying nuts 9 clamping the ring i to such body.

As shown, a unitary torque-transmitting connection is established between the several studs 1 by a iorged, stamped or cast ring it, coaxial with the wheel.

The studs I further function to mount a friction-receiving brake element in the form oi a flexible disk ll, stamped preferably irom high grade steel. Said disk is mounted on bosses II,

' inwardly projecting -irom the heads I, and is peripherally iormed with tongues I3 outwardly projectingvto engage such bosses and clamped thereon bynuts ll threaded on reduced ends oi the bosses. Preferably the tongues l3,are each formed with a corrugation l3a adjacent to and approximately parallel with the periphery of the disk body to increase freedom of lateral movement of the disk. The bosses l2 space the disk ll inwardly from the wheel so that friction may be readily applied to both of its faces. Secured to opening of such plate, and disposed to snugly accommodate the members 24 and sleeves 30, the

flange IQ of the plate l6 being conformed to said sockets, thus affording such plate ample bearing surfaces on the members engaged in the sockets. By thus mounting the plate IE, it is evident that it is held centered at the brake axis and re strained from rotation, while free to undergo a desired slight axial travel.

A dust-excluding sheet metal cover 33, best seen in Fig. 1, is preferably applied to the brake,

such cover having an outer annular shoulder 33a snugly engaging the flange ll! of the plate I6, an inner annular shoulder 33b snugly engaging the flange 5 of the axle housing, a collar 33c extending from said flange to the plate I6 and having the shape of around-cornered paralleloat their outer margins by annular flanges l8 and at their inner margins by more extensive substantially annular flanges IS. The flanges l8 project oppositely from the plates, whereas both of the flanges is project outwardly. The inner plate has a considerably smaller central opening than the outer one and is consequently larger.

To carry the plates l6 and H, two pairs of pins and 2i are rigidly mounted in the axle flange 5 and project outwardly therefrom, such pins being shouldered to seat against the outer face of said flange and engaged by nuts-22 clamped against the inner face of the flange. The pins 20, which lie above and below the brake axis, slidingly receive sleeves 23, each formed, between its ends with an exterior annular shoulder 23a and having an externally threaded portion'outwardly of such shoulder, for engagement in a socket formed in the inner end of a cylindrical anchorage member-24. The two members 24 are diametrically drilled and tapped to receive and rigidly carry the inner ends of a pair of outwardly projecting, vertical studs 25 having coned outer ends. Rotatable on each of said ends, is a torque-transmitting, dish-shaped member 26, journaled on thecorresponding stud 25 through a set of anti-friction'balls 21. A ring 28 rigidly carried by and substantially closing the open endof each member 26, is fitted around the corresponding stud 25, coacting with an annular rib 29 on the stud to maintain the assembly and confine a lubricant in the member 26. The radially journaled members 26 engage in pockets 29a, formed in the plate I! in diametrically opposed relation, by arching its flange I9 outwardly. Such engagement adapts said members to anchor the plate I"! in resistance to torque, while largely eliminating frictional resistance to sliding travel of said plate. bers 26 fit sufficiently freely in the pockets 29a between the opposed Walls thereof, to assure clearance of such members from one of such walls. As best appears in Fig. 1, the studs 25 pass to some extent through the socket members 32and are clamped firmly against such members through screwing of the anchorage members 24 on the sleeves 23. Thus said studs are securely locked against rotation in the members 24. The pinsZl respectively slidably carry sleeves 30 formed, approximately midway of their length, with annular exterior ribs 3l.. (See Fig. 5.) i

The anchorage members 24 and sleeves 30 coact to mount the plate [6 non-rotatively, while affording it a limited travel to and from the plate ll. Thus the plate I6 is formed with sockets 32 (see Fig. 2) communicating with the central The memgram (Fig. 3), and a flange 33d projecting from said collar toward the brake axis and forming the central opening 33e of the cover. The flange 3311 is apertured to fit over the sleeves 23 and 35, and the cover is held in place throughclamping said flange against the shoulders 23a of such sleeves by the members 24.

Jointly mounted in the plates l6 and H, at approximately opposite sides of their axis, is a pair of pull rods 34 (see Figs. 5 and 6) having nuts 35 thereon, to abut the outerface of the plate H. I Said rods pass freely through thepla te l6 and project inwardly considerably beyond such plate. The portions of the rods thus projecting mount a pair of brake-applying levers 36, extending upwardly'from said rods and converging toward each other to facilitate their actuation in common. The levers 35 are preferably stampings of U cross section, formed with sockets at their lower ends accommodating fulcruining ballshaped ends 31 of sleeves 38, slidable on the pull rods 34 but restrained from rotation thereon.

The other ends of said sleeves are formed with annular flanges 39, each engageable by two adjusting members 40 and 4|. The members 40 are cylindrical nuts, eccentrically drilled and tapped to engage the pull rods 34, and exteriorly threaded to mount collars forming the members 4|. Each of the latter is interiorly formed with an odd number of small longitudinal grooves 42, engageable by a detent pin 43 diametrically slidable in the corresponding nut 40, said pin having wedge-shaped ends for lodging in the grooves 42, and having a length adapting one such end to engage the interior wall of the collar between two grooves when the other end is lodged in one of the grooves. Each detent has a depression 44 at its middle, providing a flat surface to bear laterally against the outer end portion of the corresponding rod 34, to restrain the detent pin from rotation. The arrangement is such that ,the detent pins shuttle back and forth as the 40 has a lug 45 projecting from its inner end and engaging in a marginal recess of the adjacent flange 39, the ends of such recess forming radial shoulders 46, engageable by such lug to limit adjustment of the nut. pair of opposed flat faces 41 extending for a considerable portion of the rod length from the outer end of the rod, said laces preventing rotation of the rod in the plate I1, and also preventing rotation of the levers 36 and their fulcruming mem- Each pull rod 34 has a here on said rods. For applying leverage to the plate ll, each lever'is formed, a short distance from its fulcrumed aid, with a rounded protuberance ll, engaging said plate, and hardened steel disks 4! are recessed in and secured to the plate II to receive the thrust of said protuberances assasoe The levers II, which may be termed primary levers, are actuable by a pair of relatively short, duplicate secondary levers ll, of approximately triangular shape, the same being fulcrumed on pins Ii transversely carried by pull rods "Jointly mounted in the plates is and n. Nuts ls,

threaded on the outer ends of said serve to, transmit a pull therefrom to the plate l1. Said levers project inwardly from the plate "to engage actuating means, and project a lesser distanoe toward each other toengage the upper ends of the levers ll, being marginally formed with recesses 84 accommodating rounded enlargements I! terminally formed on the levers II. The ee- 4 Q 3 plates tends'to assure that willsimiiarly ailectboth.

limited floating travelaxially of the brake, in

practice such travel is confined to'the plate 11. due to coection therewith of anti-friction anchoragemeans,whereasthe plate ll must travel on slide bearings, offering much greater frictional resistance. Provision of the anti-friction mem-I- hers 2| is an important factor in deriving. a maximum eillciency from the applied braking eifortr is for the reason that theavy torque is imposed on both plates when the brake is applied and particularly during severe braking, and

transmission of such torque to the anchorage members necessarily tends toward heavy frictional to slidingof the g y resistance were not largely eliminated .by the members It, proper modulation of braking would,

be impossible and a considerable fraction of the eflort exerted in applying and releasing the brake tuating means for-the levers -50 consists of a cable It anchored to one thereof and a conduit II for such cable, terminally carrying'a fitting II abutting the other. Between the two levers, a spring ll iscoiled on said cable to urge the levers from each other. accommodate the levers II, an elongated rectangular openingis formed in the upper portion of the cover It, the latter forming a wall I marginal to such opening, and

' the friction-receiving disk ll.

In operation of the described brake, when the cable, "is tensioned, as by depressing a brake pedal (not shown), the portion ofthe cable extending through the curves of the conduit (see Fig. 8) tends to straighten out and imparts this tendency to the conduit. Since the end, of the conduit'rernote from the brake is anchored to the vehicle frame, the other end of the conduit is advanced, upon tensioning of the. cable. Hence a braking operation involves not only a pull transmitted to the lever I0 engaged by the cable, but also a thrust transmitted to the lever J0 engaged by the conduit, and this thrust and pull are equalized through the reaction between the cable and conduit.

As the secondary levers 50, are rocked toward each other due to above described actuation, they actuate the primary levers '36, causing the protuberances 48 to take effect on the plate It. The reactions of both primary and secondary levers are transmitted to the plate l'l by; the pull rods 34 and 62. Consequently the plates l8 and I! are forced toward each other and the leverage is suillcient that very powerful pressure may be applied. The lined portion of the disk I I is hence clamped between the plates l8 and I1, and the clamping pressure is a predetermined multiple of the tension applied to the cable It. Flexibility of said disk is sufficient that it may fully conform itself to the plates, even in casethe'latter are subjected to considerable distortion by frictional heat. The slightly dished form of the g A well modulated control is vital in a vehicle brake .under present day, high speed, heavy traillc would be wasted in overcoming sliding friction.

conditions, and releasing modulation is particularly vital since a braking release, producedby sliding travel, involves overcoming a static coefllcient of friction, largely exceeding thatof rela closure II for such opening being removably at-;

point remote from from the secondary levers, a-

atively moving parts, as when the brake is applied.

'- Employment of the described'primaryand sec ondary levers and the feature of using both the cable II and its conduit 51 to apply a braking I force are factors in achieving an unusually high leverage ratio, such a ratio being much'more feasible in adisk brake than, in drum brakes now employed, since thefdisk brake employs opposed frictional forces, tending to counteract distortion.

As an example of the'leverage possibilities of thedescrlbed brake, is 9 to 1 leverage may be derived from the primary levers, a 3 to 1 leverage through utilizing both faces of the disk l I, a 2 to r 1 leverage due to transmitting the effort through both the cable and conduit, and a foot pedal ratio of at least 2 to 1. Thus the very high total ratio of 216 to 1 may be had. In this connection, it is to be noted that the described brake uses the applied power so effectively as to eliminate any need for a servo or self-energizing control. This is highly desirable, since it is practically impossible to render a brake self-energizing and secure its proper esponse to a manual control under all road conditions.

wear of the linings II. In adjusting, the mechanic will turn the collars ll (usually successively) in a direction to feed them inwardlyon the nuts ll. Initially, however, said collars and nuts will turn in unison, there being less frictional resistance to turning of the nuts on the threads of the rods 34 than to turning of the collars on the larger diameter nut threads. Engagement of the lugs 45 between the radial fioulders ll willlimit turning of the nuts III plates. If such 2 to 1 leverage to effect aninitial definite adjustan approximate quarter turn, and subsequently the collars 4| will feed inwardly on the nuts. fInmits a fluid under pressure between such end and the piston, whereby the levers 50 will be rocked toward each other-to actuate the primary levers 36. A spring I1, reacting between the levers 50 45 and shoulders 46. Thus the proper working clearance will be quickly and accurately established. The eccentric engagement of the nuts by the rods 34 is utilized to impose on them a gravity tendency to establish proper clearance, their maximum radius portions being above the axes of the rods when clearance is fully taken up.

Hence if a mechanic neglects or forgets to adjust the nuts for proper clearance, after interengaging the friction linings, the nuts will swing down, when released, and automatically provide for such clearance. If the nuts fail to swing down through gravity alone, their jarring and vibration incident to vehicle travel will induce their descent. The springs 65, as has been pointed out, establish any such clearance-of the linings as is permitted by the described adjustment means. Since the lugs 45 of the nuts engage the lowermost shoulders 46, whenproper clearance is established, gravity cannot act on the nuts to disturb such clearance.

While the nuts 40 are eccentrically mounted to provide, if necessary, for their rotation by gravity, to establish a certain clearance between plates and disk, it is readily apparent that said nuts may be weighted in any other manner designed to effect their gravity rotation.

and housed partly within the pull rod I5, returns the parts to their normal positions when fluid pressure is relieved.

It is to benoted that the described brake mechanism, in any of its described modifications, permits of clearance adjustment, with considerable greater accuracy and finer increments than has heretofore been the practice. This is for the reason that the faces to be frictionally engaged move directly into and out of such engagement, and it is hence feasible to provide a considerable lesser clearance than is essential for radially acting brakes. Minimum clearance is of course highly desirable from the standpoint of deriving a maximum utility from pedal travel.

Fig. 11 is a diagrammatic illustration of a brake actuating mechanism, substituting a link and pulley arrangement for the conduit 51 heretofore described.

The levers 19 are substantially the same as the levers 50 of first-described construction, being adapted to rock toward each other in applying a brake. A cable 18 is carried on three pulleys 80, whereof one is mounted at the juncture of a pair of pivotally joined, obtusely divergent link bars 8|, while the other two are joumaled on the relatively remote ends of such bars. The first-mentioned pulley engages an opposite side of the cable from the two last-mentioned pulleys.

that tongues I3 at outer periphery. of the disk II are looped so that their ends attaching the disk to the wheel project toward the brake axis,, thus providing for increased fiexure of such tongues and increased axial play of the disk, as compared to the first-described construction. Also in this construction the inner plate 16' has an outward extension 66 projecting almost to the wheel rim 6! and serving as a heavy shield to exclude dust, gravel and the like from the brake and body of the wheel. The pins 2 I which mount the inner plate [6 are headed, as indicated at 10, to prevent outward removal of said plate, and by loosening the nuts 22' which clamp such pins to the axle flange 5', the entire brake remains attached to the wheel, on removing the latter.

Describing now the hydraulic actuating provision illustrated in Fig. 10, the secondary levers and mechanism actuable thereby does not vary from the previous description. For actuating said levers there is provided a piston" working in a cylinder 12, headed at both ends and having a sleeve bearing 13 projecting from one of such ends and slidably mounted in an end wall of the housing 60, 6|. Within such housing a yoke I4 extends around the adjacent lever, 50 to .form an actuating connection from the hearheaded against the lever 50 adjacent to such bearing to impose a thrust thereon. A pipe 16, connected to the outer end of the cylinder, ad-

One of the relatively remote link bar ends is pivoted on a fixed bracket 82, and the other is pivoted to a thrust rod 84 slidable in a guide 83 fixed in any desired manner, (not shown) in proximity to the paired levers. Said cable is connected to one of the levers and the rod 84 bears on the other. When the cable is tensioned, divergency of the link bars is reduced, causing the thrust-bar to apply a force equal and opposite to that applied by the cable. This develops materially less friction than a cable sliding in a conduit.

The invention is presented as including all such modifications and changes as come within the scope of the following claims.

What I claim is:

1. A brake comprising a pair of spaced, substantially rigid non-revoluble plates, an annular disk revoluble between such plates'and flexible to conform itself to the plates, positioning elements for. the disk engaging its outer periphery and flexible transversely of the disk to afford it axial movement, and means'for actuating the plates toward each other and into frictional-engagement with the disk, said plates and diskbeing correspondingly disked.

2. A brake comprising a pair of spaced nonrevoluble plates, a disk revoluble between such plates, two pairs of pull rods anchored to one of said plates and projecting toward the other plate, levers reacting between one pair of the .pull rods and last-mentioned plate to thrust the plates toward each other and into frictional engagement with the disk, and a common means foractuating the levers, reacting through the other pair of pull rods to thrust said plates toward each other.

. 3. A brake comprising a pair of spaced nonrevoluble plates, a disk revoluble between such plates, two pull rods anchored to one of said plates and projecting toward the other plate, a primary lever reacting between one of the pull -the revoluble asaasae primary lever, said levers serving to thrust the plates toward each other and into frictional engagement with the, disk, and actuating means operative on the secondary lever.

4. A brake comprising a pair of spaced nonrevoluble plates, a disk revoluble between such' plates, two pull rods anchored to one of said plates and projecting toward the other plate, a primary element reacting through one of said pull rods to apply the plates to the disk, a secondary element reacting between the primary ele-' ment and the other pull rod to apply the plates to the disk, and actuating means operative on the secondary element.

5. A brake comprising two non-revoluble members, a revoluble member interposed between the non-revoluble members, an anchorage member extending through and effective on one 131 A brake comprising a pair or spaced nonrevoluble plates, a disk revoluble between such plates, a, tension member anchored to one of said plates and projecting toward the other, a lever I mounted on the tension member, and actuating means for the lever, said actuating means and lever each reacting on the other of said plates at'angularly spaced pointsthereof to thrust the of the non-revoluble members, and an anchorage member for the other non-revoluble member, mounted on the first-mentioned anchorage member and rotatable about an axis substantially radial to the brake.

6. A brake as set forth in claim 5, the nonrevoluble members being annular and having pockets opening from their inner peripheries to receive said anchorage members.

7. A brake as set forth in claim 5, the rotatable anchorage member being radially adjustable with respect to the other anchorage member.

8. A brake comprising a pair of spaced nonrevoluble plates, a disk revoluble between such plates, a pair of levers, means including fulcrum members for applying said levers at circumferentially spaced points of the plates to engage the plates with the disk, a second pair of levers, re-

spectively actuating the respective levers of the first pair, and means including fulcrum members for applying the second pair of levers at points circumferentially distant from the first mentioned points, to urge one of said plates toward the other.

9. A brake as set forth in claim 8, said fulcrum members being all mounted on one of said plates.

10. A brake comprising a pair of spaced nonrevoluble plates, a disk revoluble between such plates toward each other and into frictional engagement with the disk.

14. A brake comprising a pair of non-revoluble plates, 9. disk revoluble between said plates, two tension members secured to one of said platesat points spaced angularly with respect to the brake axis,.and two levers respectively fulcrumed on the respective tension members, one ,of such levers actuating the other, and the other being efiective on the other of said plates to thrust the plates toward each gagement with the disk.

15. In a disk type applying plate having a dished form and having a reinforcing and heat-dissipating flange at each of its peripheries.

16. A brake comprising a pair of spacednonrevoluble plates, a disk revoluble between the plates, a pull rod anchored to one of theplates and projecting toward the other. plate, a lever reacting between the last-mentioned plate and pull rod to thrust the plates toward each other and into frictional engagement with the disk, a fulcrum member for the lever non-rotatably slidable on the pull rod, a nut threadable on the pull rod and effective on the fulcrum member to actuate such member toward the plates to regulate clearance between the plates and'disk, and means reacting between the fulcrum member and nut to limit turning of the nut to a fraction of a revolution.

, such members apart, and means for manually plates, one of said plates being movable to and from the other to take efiect on the disk, an anchorage member for such movable plate, rotatable about an axis substantially radial to the brake, a stud substantially radial to the brake and journaling said anchorage member, and

means for clamping said stud against the other 7 of said plates to resist rotation of the stud.

11. In a brake, an annular friction-applying plate formed at a periphery thereof with a reinforcing flange, such flange having an approximately U-shaped portion reentrant to said plate and forming a pocket to accommodate anchorage means for such plate. T

12. A wheel brake comprising inner and outer non-revoluble members, a member interposed between the non-revoluble members and revoluble with the wheel, the outer non-revolublemember being movable along the brake axis to coact with the inner non-revoluble member in restraining member, and an anchorage memher for the outer non-revoluble member rotatable about a substantially fixed axis substantially radial to the brake to minimize friction opposing said movement, due to torque.

adjusting such members toward each other to regulate their normal clearance, such means including an automatic provision energized independently of relative movement of said members for establishing apredetermined clearance.

18. A brake comprising a revoluble and a nonrevoluble member, means for frictionally interengaging such members, means yieldably urging such members apart, and means for manually adjusting suchmembers toward each other to regulate their normal clearance, such means including an inertia-responsive provision for establishing a predetermined clearance.

19. A brake comprising a revoluble and a nonrevoluble member, means for frictionally interengaging said members including a pull rod interconnecting such members, means yieldably urging said members apart, and an adjusting nut threaded on the pull rod, and effective on one of said members to advance it toward the other of the members, sueh nut induce a predetermined refrom its position interengagbeing weighted to tractive adjustment ing said members.

20. A brake comprising a revoluble and a nonrevoluble member, means for frictionally interengaging said members, means yielc'lably urging said members apart, and means for manually adjusting said members toward each other to regulate their normal clearance, including a provision for indicating definite increments of such adjustment, and an automatic provision forming other and into enbrake, an annular friction-- V dicating provision affording v 22. A brake comprising a pair of spaced non- I revoluble plates, a disk revoluble between said plates toward the other,

a part or said manual means and serving to establish a predetermined clearance. A I 21. A brake as set forth in claim 20, said inaudible indications.

plates, a pair of levers, means including fulcrum members for applying said levers at circumferentially spaced points of the plates to engage the plates with the disk, means actingas levers for actuating said paired levers in common, including' a fulcrum provision for applying said lever means at points circumferentially distant from the first-mentioned points to urge one of said and hydraulic energizing means for said lever means.

23. A brake as set forth in claim 22, said lever means comprising two spaced members respectively taking effect on the respective levers of said pair, said hydraulic means being jointly carried by said members. i

24. A brake comprising an annular revoluble member, an annular non-revoluble member movable axially of the brake to exercise a braking efiect on the revoluble member and having a pocket opening from its inner periphery, an anchorage member disposed in 'said pocket and rotatable therein about an axis substantially apart, and means for ing definite increments of 15 revoluble member, and an element rigidly mounted and adjustable substantially radially ,upon said support and forming a journal for said anchorage member.

25'. A brake comprising a revoluble and a nonrevoluble' member relatively movable along the axis of the brake and both of substantially a disk form, means yieldably urging said members manually adjusting said members toward each other to regulate their normal clearance, including a provision for indicat- 'such adjustment and an automatic provision for establishing a predetermined clearance. l

26.' A brake comprising a revoluble and a non- I revoluble member, means for friction'ally interengaging said members, means yieldably urging such members apart, and means for manually adjusting such members toward each other to regulate their normal clearance, such means including an automatic provision for establishing a predetermined clearance, such provision in-' cluding an inertia-responsive element and means for resisting flutter of such element.

EDWIN R. EVANS.

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