[1]Patented May 6, 1952 295959859 , @ C E @ UNITED STATE@S PATEN@T O@@FFI@ 2,595,859 DOUBLE DISK HYDRAUL-IC BRAI@L@E CONSTRUCTION lionier- T. Lanibibrt,' St. Josepli, and' Claude-it@@ Myers, Galien' , Mich., assignors, by,direct azid'. xnesne asgigiiments ' ',to Lambert Brak6. Corooriitidit,@ St. Jogeph,. Mich., a;@ corporati6n@@ of' lqichigafm - APPI!6ation - December 21, 1948,'96riol N6. 66,@404 5'AClaixiis'. (Cl. 188@ 9,) 2 Thb -,brosent inveiition relates@,t6.,@iniproveftlents-@, iil' thot tyge -of double-disk hydraulic' or-, fluidoper4ted brakog, diselosed in our co-pending applibation, filed'April 13, 1948, Serial No. 20,648, noW -'P 4atent -2,555,,651@, June, 5 ' 1951, and further, 5 exeinplifled in the application of Dasse and My'ers, flled October 16, 1948, Serial No., 55,178, rfoW'Patent 2,526,149 April 13, 1948. The-adVantages of'ihese double-di,k b'rake constfuctions@ hereinafter more fully explained, over 10 the drum type of brake, are now well established 15y- us, " speaking specifically, iri respect to the distributi6n @and dissipatiorr of the great heat generated ' qtdckly' incident, to @ braking actions of powerful lirakes-of the8e types employed by auto- 15 mobiles, aiiplanes, heavy trucks, trailer 'and semitrailer@-trur,ks, a-nd other vehicles, particularly wheri@-operated at high speeds, but the manner, of @Lpplying@eff ective braking forces to the braking units@ themselves has presented a problem of 20 consid@rable difficulty. These- double-disk brakes have solved many of' the@ probleriis,- such as elimination of disintegiatibn' of "loss of pedal" due to drlim@ expansion, the vaporization of brake 25 fliiid;, poor @decelbration, warpage of brake dru=, a,nd @thers which have caused many fatal acei.@ dent@g. Onelof , the mitin objects of the present improvehieiits, is - the production of ' a brake which will 30 produee-niore-braking'power'-tvith about half.the pedal pressure requir&d in drum brakes, thus lesseiiing' the dangerous driver-fatigue on long dri'vos'which has caused many accidents. A'nother; objective of great, importance, even 35 in respei3t to the@'prior constructions of this type of@ brake @ disclosed in thel prior applications hereini5ef6re referred to, is to provide- a more eff ective or'rigid@ mounting for the hydraulic cylinders which previously@have been carried by the "float- 40 ing" brake@ actuator unit assembly, enabling these'@csrlihders to be disposed more nearly coplanar with, the @ braking disks of said a8sembly to' th@reby 'transrhit, their forces in direct planes of rotation of the disks. 45 S6@@efftctive@ is'this arrangeinerit that We are able t6 acccirhplish a further objective, i. e., the red'uction of @the number of power cylinders while maintaining-'concentricity of the actuator unit a8senibly@and uniformity of the slight rotary and 50 axial:movements of the braking disks thereof, especially suitable for heavy as well as light trucks "or -vehicles@ Other; ahdfurther@ object@ and advantages - of tliel@ iilventiori I will be@ @hereina-fter@ set@ @f6rth and 55 the, novel @ f eatures: thereof 'deflhed bY@,-@ the ap:@@ pended claims. In the drawings: Flgure 1 i a@ view in elevation of W brake 'COM@: structed@ in accordance,with the-@preferred form, of this invention, with oppose d'@ sets of-' double power cylinders, one@side of the rotatablecasing,., being removed and the@mouiiting.,driving shaft: beiig: shown ift section; Mgure 2 is a@ sectional vi6w: taken about on the plane indicated by@the@ line, 2@2 of 'Figure 1,, @ Figure 3 i8 an, enlarged horizontal sectional view on the line 3-3:@ of Flgure I showing: the. details of one of,the@double'poWer cylindbrs and its mountiiig; Figure 4 is w,view@ sirnilar,to thot,of Figure; 11' of a modified form of construction utilizing onl@ a single power cylinder unit with@ opposed' roller mountings for -the brake unit@ assembly;, Figure 5 is a sectional view tqk6n about on the line 5-5 of Figure 4; Figure 6 is a view in elevation,, with one side of the casing removed@ of another modified form@ of the arrangement in Figure 1, and in which the actuator disks. abut against the ends of ' 'the power cylinders whi(h thus act@as@stops for saiddisks; Figure 7 is an external elevational view of a brake construction as in Figures 1 and 6, modiflbd: only to the extent of the disposition of the power fluid tube between the cylinders outside of the casing to prevent zany likelihood of @ vaporization@ of the hydraulic@ fluid@;:, Mgure. 8 is: a- sectional view on @ the line@ B-8 of F,-Igure 7, enlarged to! show the details, of @-construction of the upper cylinder.. Referring@to the:drawings@and'specifically describing, that form of the@ invention shown .@ in; Mgures 1 to 31 1 0 designates a rear@ drive shaft of a motor vehicle with attached @ hub: I I having the wheel flange 12. to which the @wheel 13 is con.@@ riected by means'@ of @ the@ usual boltg, 1 4. Also attolched to the hub@,iig @the- driving@@disk. , 1 5@ shaped to@ form@ one@-half of:-'tlie brake: ca;8irig, ineluding the@corhplemerital covor4pla;te, 16, which parts.are connected together by the screwg, 17. Ih8ide of the disk 15 are secured by rivets 18 the annular wear segments 19.forming one braking surface and the inner disk or cover plate 16 is likewise provided with similELr segments 19' secured by rivets 18' forming the opposite braking surface. To the rear axle housing 20 and flange plate 2 1 '@ we@- connect@'an adapter plate@ 22., as l@y means of ',the, boltg 23,L andlit@is@ this ,PI6,te that @forzts-,-the
[2]3 support for the hollow studs 24, press fitted thereIn at 2 5, and held by nuts 2 B. Upon these studs is mounted the braking unit assembly, an independent unit composed of the two complemental braking disks 27-28, conr) nected together by the transversely arranged tensioned springs 29 but held spaced from each other by the energizing balls 30, disposed in oppositely tapering seats 31, which, when one disk is rotated slightly relative to the other, cause 10 the disks to shift axially apart until their brake linings 32-32 come into frictional contact with the contiguous friction surfaces of the revolving casing 15-1 6 to produce braking action. The inner peripheries of the discs 27-28 are 15 notched, as at 33, 33, to form seats for the studs 24 and in one direction of relative rotation of these disks one of the same is held against the stud while the other disk is free to rotate slightly and a reversal of this arrested rotation takes 20 place with a reversal of the relative movement of the disks from that just stated. The principle of the braking action of this construction is disclosed in both of the applications first above referred to, but the important distinc25 tion in the construction lies in the mounting of the power cylinders for impart-ing the relative rotary movements to the disks 27-28. Heretofore these cylinders have been mounted on one side of one of the disks of the braking unit as30 sembly and thus they partook of its floating @movements, but in the present construction we mount both the upper cylinder 34 and the lower cylinder 35 rigidly on the adapter plate 22, by the bolts 36, as best shown in Mgure 3 of the 35 drawing. This disposes the cylinders more in the same plane as the disks. Moreover, each of these cylinders is what we term a double cylinder because of the fact that two opposed pistons 37-38 are mounted in each 40 while the piston plunger 39 is seated against the lug 39' of the outer disk 27 and the opposite plunger 40 is seated against the lug 401 of the inner disk 28. Between the two pistons of each cylinder iS 4,-, mounted an expansion spring 4 i which holds the plungers 39-40 in contact with the respective pistons and the lugs 391-40, in the absence of fluid pressure in the spring chamber betweeli the pistons. 50 The lower cylinder 35 is constructed and arr . anged similarly to the upper and a tube 42 establishes communication between the two cylinders which are supplied with pressure fluid in the conventional manner through the hose nipple 43 of the upper cylinder, which latter is also provided with the bleeder plug 44. A strip of insulation 45 is disposed between each cylinder and the actuating disks so a-s to prevent transfer of heat from the latter to the 6tl fluid in the cylinders which would otherwise tend to vaporize the fluid when not so protected. . Incidentally, we. employ in this construction an automatic adjuster for taking up any substantial wear between the friction surfaces of the 65 brake occurring during use of these bralces, this being generally composed of the adjuster rod 46 connected to one actuator disk and passing through the bracket 47 connected to the other disk and loosely pivoted at the end, as at 48. 70 A spring tensioned locking washer or clutch disk 49 engaging the rod 46 normally prevents movement of the rod in one direction while permitting it to shift in the other direction when wear between the friction surfaces of the casing and 70 2,595,859 4 the disks takes place, thus maintaining constant the running clearance between these friction surfaces at all times. No claim is made herein to this iinportant feature, since this is the subject matter of the Dasse and Myers application hereinbefore referred to. Coming now to the form of brake construction shown in Mgure 6, this differs little from that shown in F-igure 1, being distinguished therefrom mainly by the use of the power cylinders as stops for the normal positioning of the actuator disks and the further elimination of the mounting studs 24 of the preferred form shown in Figure 1. That is to say, the lug 39a is formed with a flat seat at 50 to seat against the flat end face of the cylinder 34a. The lug 40a is likewise form ' ed. Furthermore, in this form the disks are tensioned in the normal brake-released Position by two additional springs 51, 52, the former being connected to the cylinder casting at one end and to the lug 53 of the outer disk, aiid the latter being also connected at one end to the opposite end of the cylinder 34a and at its other end to the lug 54 on the inner disk. otherwise, the parts of this brake constructioh correspond to the preferred form of Figure 1, and, therefore, need not be further referred to other than, as stated above, the studs are omitted due to the selfcenterilig support which is provided by the pistons and the tension springs 29, 51 and 52. In Figures 4 and 5 we illustrate another modification of the brake construction as generally shown in Figure 6, and it bears such close similarity as to have the same reference characters for the parts illustrated with the exception of those now to be referred to. In this construction, it will be observed that only one cylinder, namely, the upper one, is employed, and its ends constitute the stops for the actuator disks as hereinbefore described with reference to the form shown in Figure 6. Instead of using the lower cylinder, we have provided two sets of roller supPorts, each comprising a pair of side-by-side rollers 55 having a bearing on thecooperating surfaces 56 formed on the inner periphery of the respective actuator disks. These rollers 55 are carried by the stud 57 secured to the adapter plate 22 by means of the nut 58. It will be noted that the raised surfaces or tracks 56 for these rollers prevent any possible contact of the rollers with the braking surfaces carried by the disks, and by disposing the sets of rollers at the points shown clearly in Figure 4, having regard to the position of the cylinder 34a, the actuator disks or braking unit assembly will be held in its concentric relation at all times during the use of this brake construction. This form of brake is particularly suited for lighter trucks and trailers and possesses sufficient power, due to the double piston arrangement of the single cylinder, to provide effective braking action at all speeds, and such construction is much cheaper to manufacture in view of the elimination of the second cylinder casting and its parts. The foregoing leaves only the description of the construction employed in connection with the illustrations of Mgures 7 and 8. The only change in this form with respect to what has been described in Figures 1 and 6 resides in the positioning of the communicating fluid pressure conduit 42a outside of the revolving casing composed of the disc 15 and its cover plate 16 as set forth clearly in relation to the construction of Figures I and 2. This Insures against the trans.
[3]5 fer of heat to the pressure fluid since it is disposed in position to be cooled by the air during the movement of the vehicle, such as at the time of brake application. However, in view of the quick dissipation of heat by the fin construction of the rotating casing and the use of double disks of the braking unit assembly, the mounting of this tube within the casing, as shown in Mgures I and 6 of the drawings, is entirely permissible, so that the two mountings of the communicating tube are optional under all conditions of use of this form of brake apparatus. The operation of. the various brake constructions as disclosed herein will be obvious from the foregoing and is generally similar to that described in the co-pending applications hereinbefore referred to. Briefly summarizing the operation, it will be understood that the pressure fluid is admitted to the power cyiinder or cylinders in any suitable manner, as by the conventional application of a brake pedal (not shown) or other control member. When so admitted, the pressure within the power cylinder or cylinders causes the opposed pistons to move outwardly away from each other in each cylinder, thereby producing a thrust upon the plungers 39-40, which thrust is transmitted to the disks 27-28, causing relative rotation of the latter. This relative rotation of the disks produces an axial separation of the disks by means of the balls 30 disposed between the disks and seated in the inclined camming seats 31 in the respective disks. The axial separation of the disks causes the same to engage the opposeci braking surfaces on the inner faces of the rotatable casing 15-1 6, such initial engagement causing a slight further rotation of one of the disks 2 7-2 8 relative to the other to increase the braking effect in the nature of a servo or self-energizing action. The braking action is equally effective in either direction of rotation of the casing 15- 1 6, which is particularly advantageous in the case of automotive or vehiele brakes. When the pressure fluid is released, the disks 27-28 will automatically return to their initial positions, under the influence of the tension springs 29 and/or 51-52, with the balls 30 located at or near the bottom of the inclined recesses 31, preparatory to subsequent brake applications. By reason of the fact that the power cylinder or cylinders is or are stationary at all times, the plungers 39-40 are so constructed and arranged as to permit of a slight rocking movement thereof against the pistons and against the lugs with which the plungers engage at their outermost ends in directing the thiusts on the disks 27-28, thus allowing relative rotation of the disks incident to brake application, as well as reiative axial displacement of the disks which takes place during braking engagement of the disks with the braking surfaces of the casing 15-16, and disengagement thereof. While the specific details of construction have been herein shown and described, the invention is not confined thereto as changes and alterations may be made without departing from the spirit thereof as deflned by the appended claims. 2,595,856 6 We
