USRE17344E - anderson r - Google Patents

Description

ATTORNEY 3' Sheets-Sheet L \N N. NW N ER c. o. ANDERSON AUTOMATIC BRAKE ADJUSTING MECHANISM Original Filed March 26, 1927 July '2, 1929.

July 2, 1929. c. o. ANDERSON R 7.3

AUTOMATIC BRAKE ADJUSTING NECHANISI Original Filed March 26, 192'? 3 Sheets-Sheet 2 2, 1929- c. o. ANDERSON AUTOMATIC BRAKE ADJUSTING MECHANISM V Original Filed March 26, 1927 3 Sheets-Sheet iNVE NTOR ATTORNEY l. llll llll llll Reissued ay 2, 1929.

UNITED STA TES CHARLES 0.. ANDERSON,

on OMAHA, NEBRASKA.

PAT

An'roMA'rro BRAKE-ADJUSTING MECHANISM.

Original lilo. 1,691,325, dated November 13, 1928, Seri aI No. 178,669, filed March 26, 1927. Application for reissue filed April 10, 1929.

slack or clearance between the brake-shoes and wheels when the brakes are in release a position. It is the object of my present invention to provide, 111 brake-ad usting mechanism of the above character, certain refinements of structure whereby toreduce to a' minimum the wear of thenicchanism due to vibration, lack of lubrication, and the introduction of abrasive materials into the working parts. A further object of my invention is to provide means for preventing excessive action of the adjusting means, such as to cause separation of the adj Listing-screw and the head in which said screw works. A further object is to provide means for preventing looseness'between the workingparts or the adjuster, whereby to enable operation thereof by the relatively small resisted movement of the brake-levers in so-called' bcai'nless brake-rigging, wherein the brake-shoes are closely associated with the trnclelevers 111w stead of being carried at the ends of brake vbeams to WlllCll the truck-levers are'connected at the center. i

Further, it 1s an object to maintain adehnite normaloraverage friction between the" V adjusting rod and the forked head, thereby not only avoiding rattling, due to looseness, but also preventing back lash. or slippage or therod whilethe clutch sleeve is beinginoved I reversely, i. e., moved for, the purpose'of tingitto a position for turning theadjnst ing rod to take up slack. v

In theaccompanying drawings: I Figure 1 is a longitudinal section of a truck having applied tothe brake-levers at oneside thereof. an adjusting mechanism embodying myinvent'ion.

Figure 2 is a plan view of the same. 1 Figure 3 is a detail end view of the adjustin mechanism and a or ti on of the live trucklever.

Figure dis adetail transverse section on the line 4- -4; of Figures 5 and 6. Figure 5 is a mechanism; p p

t Figure Gis a longitudinal section of the same. a

Figure 6 is a side view,partially in longig I tudinal section, showing a modified structure;

sideview of the adjusting Serial No. 354,117.

nal section of thesforked head showing a frictional' means which prevents back lash and loosenessbetween the rotatable head and the forked head.

Referring to Figures 1 and-2, there are shown portions of a truck of a type which has recently come into use for electric railways, and wherein the brake-rigging is commonly designated as beamless although in fact the brake-shoes are carried on brake beams. In trucks of this type, in order to provide space for electric motors hung between the aXles 10 and the cross-beams 11 of the truck-frame, the live and dead truck-levers of the brake-rigging are not connected with the central parts of the brake-beams 12', and the main transverse portions of said beams are arranged substantially beneath the bolster 13. In this class of brake-rigging, in orderto attain proper equalization of the braking-pressure at the brake-shoes 14, there are employed on eachtruck two live-levers 15 izing-lever 18 to which thebraking power is applied. The release-springs 19 are also connected with equalizing-lever 18. The upper. end of each dead-lever is fulcrnmed on a link 20 connected with the cross-beam 11.

i The intermediate portions of the levers 15 and 16 are connected with the brake-beams 12 by brackets 21 which are secured to said beams close to the ends thereof onwhich the shoes llare' attached, and, the brake-shoes and beams are supportedby hanger-links 22 pivotally connected with the side-frames 23 of thetruck. "In the illustrated structure the lower ends ofthe levers15' and 16 are operatively: connected with'each other by my improved brake-adjuster, which is automatically extensible longitudinally to compensate for wear ofthebrake-shoes. i

In the "bral re-rigging of the class above mentioned, and in other cases, such as in locoinotive truck and driver-"brakes, where the noted.

brake-levers are closely associated with the brake shoes, Without the interposition of a considerable lengthof brake-beam, the movement ot the levers in applying'and releasing the brakes is relatively small, because substantially all movement of the levers is immediately effective upon the brake-shoes, and alter the brake-shoes are in contact with the wheels very little excess movement of the levers is required to compensate for springing of the brake-beams as the braking pressure is increased. In applying, to such brakerigging, automatic slack adjusting means which. depends for its operation upon variations in the angular relation of the live-lever and the connecting member between said lever and the dead-lever, the adjusting meansmust be of such construction that'it will operate eiiiciently and continue to so operate, without the excess travel of the truck-levers usually caused by springing ot the brake-beams; and it is this fact which necessitates certain of the refinements of structure of the slackadjusting mechanism, which constitutes the subject matter of this application. It will be understood, of course, that my improved adjusting mechanism is applicable to the older types of brake-rigging, and is not limited to brake-rigging of the special types above The adjuster mechanism is best shown in Figures 3, 4, 5, 6 and 7, and, referring to said figures it will be seen that at the end oining the live-lever 15 there is a forked head 24 which straddles the end of the live-lever and is pivotally connected therewith by the pin 25. The jaws of said forked head have upwardly extended cheek-plates 26, formed integrally therewith and adaptedto closely embrace the sides of the lBVG1','LS best shown in Figure 3, for a purpose which will presently appear. A portion of the pin25 is extended laterally of the head to form a fulcrum for the bell-crank or rocker-27 which is retained thereon by a nut 28 screwed upon. the threaded end of the pin, a'coil spring 29 being disposed between said nut and the hub of the rocker to trictionally restrain. movements of the rocker about the pin, and to thus reduce wear and rattling of these parts. One arm of the. rocker extends approximately horizontally andvterminates in a ball 30 which fits within a socket formed by a U-shaped flange 31 on the side of the clutch-sleeve The other 211311101? the rocker extends up approximately parallel with the lever. 1.5, and has atorked upperend portion which straddles the laterally p t-ejecting end of the fulcrum pin .83 Which connects t-lieleverwith.

the bracket 21 ofthe'brake-beam. One side of the forked end o tthe arm is tormcd by a finger34 which has athreaded shank screwed through the main part, of the'arm, whereby the space between the jaws of the fork may be adjusted, a lock-hut 35 being provided on the threaded shank for holding the same in adjusted position.

The head 24 has a tubular body-portion 36 over which the clutch-sleeve 32 tits rotatably,

and through which is extended the rotatable adjusting-rod 37. Within said tubular portion 36 said rod 37 has a conical shoulder or offset 38 which fits within a conical seat provided within the bore of the head, said shoulder being held against said seat by the pres sure of a spring 39 disposed around the re duced end-portion 37* of the rod and retained. thereon by a-nut 40 screwed upon the threaded end of said reduced portion. Upon the rod 37 adjacent to the end of the tubular body 36 is disposed a conical clutch-collar 4-1 which is secured to the rod by a transverse pin Said collar 4-1 is inclosed by the sleeve 32 which is bored to provide a conical seat for engaging the collar, and the sleeve is pressed yieldingly longitudinally of the rod to frictionally engage said seat 32 with the clutch-collar, by means of a spring 43 dis posed around the rod. at the end of the sleeve and held against the same by a collar 44 secured to the rod by a transverse pin 45, as shown in Figure 6. The main portion of the rod 37, at the end opposite the clutch mechanism, is threaded and screwed into the thrcarb ed intermediate portion 46 of the tubular head 4-. One end of said head 46 is closed and has a pair of aws 47, formed integrally therewith and adapted to straddle the lower end of the dead-lever 16, the latter being pivotally connected therewith by a pin 48 passing transversely through any of a plurality of holes 49 in the aws. T he adjlisting-screw termed by the threaded part of therod 37 is covered at all times by the chambered endportions of the head 46, the open end of said head being extended to normally engage the smooth or unthreaded portion of the rod, and thus forming the guide 50 for holding the head and rod in alignment addi tioually. to the screw-threaded engaging portions of said members. In the side of the head 46 adjacent to the closed end thereof. an opening is formed, which is normally closed by a screw-plug 5]. By connecting a grease-gun with said opening a suitable lubricant may be forced into and through the head, so as to flow toward the open end thereof, past the adjusting-screw, and thus tend to eject from the bore of the head any dirt, grit or abrasive m aterial which may have entered the same. The chambered end-portions 0f the head form reservoirs for retaining a quantity of grease sufficient to lubricate the screw during an extended period of use. At the upper side of the threaded intormediate portion of the head 46 atubular boss 51 is formed thereon, the outer end of the opening thereof being normally closed by a screw-plug 52. At the inner end of said opening, adjoining the screw, is disposed a ball 53 which. is pressed yieldingly against 1'" I thevscrew'by a coil spring 54 disposed between I thereof, one side of said notch being radially undercut so that when the ball drops into the notch, as shown in Figure 4, it will prevent; further rotation of the screw in the die the spri reduced toa minimun'iirection tending to withdraw the screw from the head. The-other sideof the notch is so inclined that when the screw is turned so as to'enter the head the ball will he lifted out of the notch and the turning movement not interrupted.

"For use where the adjuster is subjected not only to lateral or Whipping stressesbut also to longitudinal shaking and vibration, it is desirable to prevent wear of the adjustingscrew and the threaded part of the head, by maintaining between the head and screw a longitudinal pressurewhich is constant in direction. This result is attained by the special meansillustrated in Figures'fi", ,8 and 9, wherein the guide member at the open end of the head 46' .is formed as apackinggland screwed into the head, the gland being recessed at its inner end to receive a packing 56 which is engaged the end of a sleeve 57 fitting slidably over the rod 37. At its inner end the sleeve 5? engages a spring 58 disposed about the rodfand the inner end'of said spring engages a nut 59 which is screwed onto the threaded portion of the adjusting-rod. The nut 59 is cyline drical "except for a V-shaped projection 59 at one side which is extended into a similarly formedpocket 60 at the side of the head, whereby rotation of the nut within the'hea'd is prevented, while longitudinal movement, is pern itted. In assembling the parts the nut 59 is inserted edgewise through the open end of the head, and'turned to a transverse position after theprojection 59' is in positionto enter the pocket60. The rod then screwed through the nut, sodas to project slightly p'astthe inner face thereof,

before starting to enter the adj acentthreade d portion of the head. When the screw 1s started in said threaded portion, the nut Wlll r maintain its longitudinal position relative thereto, asthe rotation of the screw Wlll cause it to advanceequallythrough both the nut and'the head." The assembly is completed by inserting the spring 58 and sleeve 57, then screwing the glandet)" into the head, whereby 58 is compressed against the side which is thus caused to exert a The m of the nut, thrust upon the ad usting-screw.

, strength of the spring 58 is such that thelongitiiidinal pressure between the partsremains constant in direction, regardless of any shal'iing or vibratio-nto which the same are subjectechand wear of the threads by rattling or hammering from. such vibration is thereby In considering the operation of the ad.- juster as 'awhole, it will be firstnoted that the clutcl'i-sleeve 32 is pressed against the clutch-cone 41 with a constant'and uniform pressure, proportional to the strength of the spring 43, and any rotational movements of the sleeve thus tend uniformly to be imparted; to the adjusting-screw or red 37 by the frictional clutch connection. The conical shoulder 38 of the adjustingaod, by being pressedinto the seat therefor in the head 24:, forms a clutch-like frictional connection between said head and the adjusting rod. The spring 39 keeps the longitudinalpressure at the conical shoulder constant in direction, as the pressure of said spring is greater than any tensile stresses to which the adjuster'is normally subjected, but the total pressure stantially in proportion to the braking" pressure exerted upon the shoes. v t

Duringa normal brake-applying movement of the live-lever, such as occurs when the slack or clearance between thebrakeshoes and wheels is not excessive, the change in ti'ie angular relation of the live-lever to the adjuster mechanism merely causes the fulcrum-pin 33 to movebetween the aws of the rocker 27, and causes no movement of the rocker relative ,to' the head. 24. then the slack is excessive l'iowever, the increased n'iovement of the live-lever in applying the brakes causes the pin '33 to engage thefinger .or jaw of the rocker and to move thelatter slightly about its: fulcrum on the pin 25; Such movement of the rocker is communicarted to the clutch-sleeve 32 by the ball-head 30 of the lower rocker-arm, causing the clutch-sleeve to be rotated slightly relatively tothe headQt, and when the brakes are then releasetilthe movement is reversed and the clutch-sleeve is rotated slightly. in the opposite direction.

These oscillating, or alternat n rections be imparted. ec 'ually to the adjusts in -rod no effective ad'ustment ofthe rod willjbe' caused, and the length of the brakd rotative, movements {of the clutch-' slee e tend tobeimparted by said sleeve to the lever-ccnnection, formed by the heads 24 and 46 and the rod 37, will be unchanged. ation of the rod 37 occurs, however, when the clutch connection between the sleeve 32 and collar ll is caused to slip during the moven'ient in one direction. The clutch-friction is so proportioned that such slipping of the clutch connection will occur during the resisted portion oi? the brake-applying movei'neut, or after the brake-shoes have engaged the wheels and begun to exert some pressure thereon, whereby the longitudinal compression of the bralze-lever-connection causes an increase of the frictional resistance to retation oi the screw ithin the head 46 and oi? the conical shoulder 58 within the seat therefor in the head 24. After such. slippage of the clutch has occurred during a brahe-applying movement, then at the end of the succeeding brake-releasing movement the adjusting-screw is turned slightly in the direction required to elongate the ti'uclr-lever connection and reduce the slack. If a sufficient reduction of the slack is effected, subsequent applications of the brakes will cause no movement of the rocker and clutch-sleeve, but the adjusting action will be continued at each application and release of the brakes until the excessive slack is fully compensated.

As hercinbetore noted, the portion of the brakedever movement which is e'tlective to cause actuation ot the automatic slack-adjusting means, is the resisted motion which occurs after the brake-shoes have engaged the wheels, and subsequent to the free motion during which the brakeshoes are merely being moved toward the wheels. Obviously, in brake-rigging of the types first herein mentioned, or in which the brake-levers are closely associated with the brai-;eshoes, the resisted. portion of the brake-applying motion 071' the levers is of small extent and is merely iat which results from the slight resilience oi? the parts intermediate the trucklevers and brake-shoes, and the slight displacement of the wheels of the truck, allowed by looseness oi? the journal-boxes and resulting from he brake-pressure against the wheels. In order that the limited amount of resisted motion of: the levers may be fully efl'ective in actuating the adjuster, substantially all loosencss and lost motion between the parts of the adjusting mechanism must be eliminated, and wear thereof cou'ipensated so that looseness will not occur after a period of use; In my improved adjuster the first of the several means, employed for the foregoing purpose, consists in the provision ot' the cheek-plates 26 on the head 24. Said cheek-plates limit to a minimum any rotational movement of the head 24 about the axis of the adjusting-rod 37, which might otherwise result from looseness of the pin 25 which connects said head Qt with'the livelever 1f The second'means for limiting or reducing lost motion in the adjusting de vice consists in the extension of the rod 37 entirely through the head 24, and the provision of the spring 39 upon the extended portionot the rod, whereby the shoulder 38 is held firmly seated in the head, rattling and wear between the head and rod is minimized, and a definite normal or average .friction is assured between the head and ment thereof, assures enicient lubrication of the adjusting-screw, protects the screwthreads from corrosion, excludes dust and abrasive material from the screw, and provides the supplemental guide 50 to assist in maintaining the alignment of the head and screw. The lock or latch device, formed by the ball 53 and the notch 55 in the adjusting-serew, prevents the accidental withdrawal of the screw from the head l6 by the continued operation of the adjusting means, should the renewal or". worn brake-shoes be neglected or loss or breakage of parts occur, tending to cause the extension of the adjuster beyond a proper range of adjustment thereof. Finally, the provision of the nut 59 and the spring 58, in the special construction shown in Figure 8, causes a longitudinal pressure, constant in direction, between the adjusting-screw and the threaded part ot the head 46, and thus prevents longitudinal play, rattling and wear between said head and the screw. i

Further, the presence of the ball 53 and spring 52 tends to prevent rattling of the screw, in the threaded part of the head 46 should the same become somewhat worn and should no device such as the parts 58 and 59 (Figure 8) be used, see Figure 6.

Now, having described my invention, what I claim and desire to secure by Letters Pat cut is:

1. In an automatic slack-adjuster for brakes, a brake-lever-conuection con'iprising terminal heads connected with the brake-levers, and an intermediate rod connecting said heads and rotatable relatively thereto, a portion of said rod being threaded and engaging threaded portion of one head, means for maintaining between the rod and the other head a longitudinal pressure constant in direction, a clutch-sleeve mounted rotatively upon said rod and having a constant frictional a pivotally connected withthe brake-levers, an

intermediate rod connecting said heads and rotatablerelatively thereto, a portion of said rod being threaded and engagng a threaded portion oft the adjacent head, and means for maintaining betweensaid rod and each of the heads a longitudinal pressure which is con stant 1n d1rection.

3. In a slack-adjusterv for brakes, a brakelever-connection comprising terminal heads and an intermediate threaded rod connecting saidheads and rotatable relatively thereto tovary the length of the connection, means for rotating said rod, means pivotally connecting said heads w th the brake-levers, and

b means formed integrally with one of the heads and closely embracing the ofthe respective brake-leverat a substantial distance from the pivotal axis, whereby to prevent rotative movement of said head relative to said lover about the rod-axis when the pivotal connection of the head and lover becomes worn and loose.

4.; In aslack-adjuster for brakes, a brake lever-connection comprising terminal heads plvotally connected with the brake-levers,

and an intermediate rod connecting said heads, said rod having at one end a screwthrea'ded connection with one of the heads and having at the other end a shouldered reduced portion extending through the other head and rotatable therein, the shouldered portion engaging a seat therefor insaid head, and means pressing said shouldered portion yieldingly against said seat. Q I I 5. In a brake-lever connection, a rotatable adj listing-rod having'a threat'led end-portion, a head having at one end therecd jaws for pivotal connection with a brake-lever and having a tubular body inclosing all of the tl'lreadec l portion andpart of the unthreaded portion'oi the. adjustingrod, said tubular body having arr-internally threaded part engaged by the threaded portion of the adjusts ing-rod, a guide carried at the end of the tubular body and fitting about the unthreaded portion of the adj usting-rod, a nut disposed upon the threaded portion of the adjusting-1nd within the tubular body between said guide and the threaded part of the body, said nut and the tubular body inter-engaging to prevent relative rotation thereof, and a spring disposed about the rod between the guide and said nut for pressing the latter longitudinally toward the threaded part of the body.

6. In an adjustable brakedevenconnection, an adjusting-screw, a head havmg a threaded portion engaged by said screw, a nut disposed upon said screw, means for preventing relative rotationof said nut and the head, a spring engaging said nut and pressing the same longitudinally of the screw, and an abutment held in fixed longitudinal relation to the head and engaging said spring to hold the same against the nut. I

7. In a slack-adjuster for brakes, a brakelever-connection comprising terminal heads connected with the brake-levers, and an adjusting rod connecting said heads and rotatable relatively thereto, a portion of said rod being threaded and engaging a threaded por tion of one head, a clutch-sleeve mounted rotatively upon said rod, means for maintaining a uniform frictional engagement between said sleeve and the rod, means for actuating. the clutch-sleeve in directions alternating astne brakes arev applied and released, and means for maintaining between said adj Listing-rod and each of the heads a longitudinal pressure which is constant in direction. l

8. In a slack-adjuster'for brakes, a brakelever -connection comprising terminal heads pivotally connected with the brake-levers, and anadjusting-rod connecting said heads and rotatable relatively thereto, a portion of said rod being threaded and engaging a threaded portion of one head, a clutch-sleeve mounted rotatively upon saidrod, means for actuating the clutch-sleeve in directions alternating as the brakes are applied and released, means for maintaining. between said adj Listing-rod and each of the heads a longitudinal pressurewhich is constant in direction but-variable in amount according to the longitudinal stresses between the brakelevers, andv means for maintaining a uniform clutch-friction between the clutch-sleeve and relatively rotatable to vary the length of the connection, means frictionally connected with one of said members for rotating the same to elongate the connection when'the slack is excessive, and a detent carried by one of: said threaded members and yioldingly "en gaged with the other, the latter member hav ing a portion engageable with said detent to prevent extension of the connection beyond a predetermined limit. 10. In a slack-adjuster for brakes, an adj Listing-rod having a threaded portion, a tubular head inclosing the threaded portion of the adjusting-rod'to form a housing there for, said headbeing internally threaded to engage the threaded portion of the rod, the head having a lateral opening intersecting the threaded portion in which the rod is enafter the brake-shoes engage the gaged, a member movably disposed in said lateral opening, the rod having an undercut recess in the side thereof adapted to register with said lateral opening, and means for actuating said member to enter said recess as the latter comes into register therewith during rotation of the rod and to thereby prevent further rotation of the rod.

11. In a slack-adjuster for brakes, a brakelever connection having a forked head straddling the brake-lever, an adjusting-rod rotatively connected with said head, a fulcrumpin extending transversely through the forked head and brake-lever to pivotally connect the same, and cheek-plates carried by the head and arranged to closely embrace the sides of the lever at a distance from said fulcrum-pin to limit movement of the head about the axis of the adjusting-rod when the fulcrum-pin becomes worn and loose.

12. In a slack-adjuster for brakes, a brakelevcr-connection comprising terminal heads pivotally connected with the brake-levers, and an intermediate rod connecting said heads, said rod having at one end a screwthreaded connection with one of the heads and having at the other end a shouldered reduced portion extending through the other head and rotatable therein, and means main taining frictional connection between said rod and said other head.

13. In a slack-adjuster for brakes, a brakelever-connection comprising terminal heads pivotally connected with the brake-levers, and an intermediate rod connecting said heads, said rod having at one end a screw threaded connection with one of said heads, the other of said heads having tubular portion to receive said rod, said rod having a shouldered reduced portion extending through said other head and rotatable therein, and means for maintaining frictional connection between said rod and said other head.

14. In a slack-adjuster for brakes, a brakesaid rod, said rod having a shouldered reduced portion extending through said other head and rotatable therein, and means for main taining a definite normal friction between said rod and said other head.

15. In a slack-adjuster for brakes, a brakelever connection comprising terminal heads pivotally connected with the brake-levers, and an intermediate rod connecting said heads, said rod having at one end a screw threaded connection with one of said heads, the other of said heads having a tubular por tion to receive said rod, said rod having a shouldered reduced portion extending through said other head and rotatable there-- in, a nut threaded on the reduced portion of said rod and holding said rod and said other head against coming EL132L1'i ,'LI1ClH1BHDS cooperating between said rod and said other head to maintain friction between the same for the purposes described.

16. In aslack-adjuster for brakes, a brakelever-connection comprising terminal heads pivotally connected with the brake-levers, and an intermediate rod connecting said heads, said rod having at one end a screw threaded connection with one of said heads and having at the other end a shouldered reduced portion extending through the other head and rotatable therein, and means maintaining f iction'al connection between said rod and one of said heads for the purposes described.

17. In a slack-adjuster for brakes, a brakelever-connection comprising terminal heads pivotally connected with the brake-levers and an intermediate rod connecting said heads, said rod having at one end a screw threaded connection with one of said heads and having at the other end a swivel connection with the other head, a clutching means cooperating with said rod and one of the brake-levers for automatically turning said rod for the purposes specified, and means maintaining frictional connection between said rod and one of said heads for holding ,said rod against turning backwards during the reverse movement of said clutching means.

CHARLES O. ANDERSON.

Images