US2694472A - Automatic slack adjuster mechanism - Google Patents

Description

Nov. 16, 1954 G. B. DoREY AUTOMATIC SLACK ADJUSTER MECHANISM 5 Sheets-Sheet l Filed Dec. 29 1951 A INVENTOR,

s y .Iv 5 Y Nov. 16, 1954 G. B. DOREY AUTOMATIC SLACK ADJUSTER MECHANISM 5 Sheets-Sheet 2 Filed Deo. 29, 1951 wwmwm .Flin/ g,

Nov. 16, 1954 G. B. DoRr-:Y

AUTOMATIC SLACK ADJUSTER MECHANISM Filed DeO. 29, 1951 INVENTOR S ma Nov. 16, 1954 G. B. DOREY 2,694,472

AUTOMATIC SLACK ADJUSTER MECHANISM Filed Dec. 29. 1951 5 Sheets-Sheet 4 Facfws Flsfqz FscTM INVENTDR ffm? Nov. 16, 1954 G. a. DoREY AUTOMATIC SLACK ADJUSTER MECHANISM 5 Sheets-Sheet 5 Filed Dec. 29, 1951 INVENTOR- United States Patent() 2,694,472'y AUTOMATIC SLAGK 'DJ-USTR MECHAN ISM George B."l`)or'ey, Vlestniount,A Quebec, Canada, assgnor to Continental Transport Appliances, Limited, Montreal,l Quebec, Canada, a corporation 'of -Canada Application December 29, 1951,"Serial No.v 264,033

3 Claims. (Cl. 18S-202) The invention relates to'an'improved -automatic slack adjuster 'mechanismfo'r the-'brakes of 'railway carsandthe like.

This invention constitutesan improvement 'over 'my inventions disclosed in Amy co-'pending application, Serial No. 152,061, led M ar'chV 27, 1950,' now Patent No. 2,646,139 of July 21, 164,871, led May 29, 1950, now-Patent No. 2,646,140; application Serial- No.v 179,046; led August vl2, 1950, now Patent No. 2,646,'137,'July :21,l 1953;-y application Serial No. 191,625, tiled October23, 1950, 'now Patent No'. 2,646,138;applieation Serial No. 208,396,1i1ed J anli-y ary 29, 1951, now abandoned;v application Serial No. 210,747, led Februaryl 13,1l 1951,A nowl Patent gNo. 2,646,141, July '21, 1953;' and -application Seriall No. 210,748, tiled February 13, 1951.

The `objects yof lthe-invention amongothers are to provide an automat-ic slack adjuster Imechanism Ywhich is of Vsimple 'construction' and*I available as- -a package unit suitable-for application: to various typesof existing equipment without modification; to provide'` springoperated slack 'adjusterl ha'ving a sprin'gf operatingimecha nism in whichthe parts; are rdisposed in telescopic relation to render the unit self-adjusting for-various lengths of push rods; to provide an mprovedfbellfcrank type of operating lever vmechanism' for operating La screwthreaded takeup device on a connection rod; to prov'ide" an improved andsimpliled U-shaped bracket 'for supporting va pivotally mounted bell crankloperating lever associated with a take up device; andto provide -an improved f abutmentv structure'. which may be' readily threaded onthe stem of apushf rod for lenergizing a spring on movement of a -push rod ina brake "applying direction.

For comprehension -ofl thel invention reference vmay be had to the accompanying'drawings wherein:

Figure 1 is a plan-view yof a-portion` ofs a railway car showing the invention appled'linconnection with the brake gear of the car.`

Figure 2 is a-plan view-on an enlargedscale of the outer end of the brake cylinder together with the spring mechanism and the push rod, the `parts being shown with the brake and spring mechanism in`released' position.

Figure 3 is a longitudinal elevational view of'the structure shown inFigur-e -2.

Figure `4 is a vertical sectional view taken through'the spring -mechanismy onV a linel 4--4 'of-Figure'S.

Figure-5 is a vertical -sectional view onfan-enlarged scaletaken ona line 5 5 of Figure -l showing' the position of they bellcrank operating `lever in'rela'tion 'to the center connectionfand brake cylinder;

Figure 6is a vertical lsectic'nalfview*on an enlarged scale takenon a line 6-6 of Figure'2.`y

Figure 7 is a vertical longitudinal sectional View taken through the spring mechanism on a line 7 7 of Figure 2, showing the spring mechanism in released position.

Figure 8 is a view similar to Figure 7 yexceptv that the'spring mechanism is shown in partially compressed positionwith the locking pawl `in engagement -with-the third retaining tooth.

Figure 9 is a view of the outer endfof lthe mechanismvv shown in Figures 7 and 8 except that the pawl isshown in position of release as the spring retaining escapement operates.

Figure 10"is a view similarl to'Figure 9 except-that the locking pawl is kshown in' the overbalanced Anon- 1953; application Serial No."

2,694,472 Patented Nov. 16,A 1954 lCC 25'/ operative positiony assumed bythe pawlduring the-return of the spring.

Figure ll isa plan view-on anenlarg'ed -scaleof the push rodA with i the combined clevisfand"fabutment'applied thereto.

Figure12 is a:longitudinal--elevationale'vieweof the push rody sh'own 1in-Fi`gufre 411.1 Y

Figure l13 is an endf'elevational-"viewiof'the'pushrod assembly shown in Figure=12 as viewed'from'rightto left.

Figure 14 is a planviewV oflfthe' push'rod abutment plate.

Figure 15 is a flongitu'dinal elevationalwview -of-'the abutment plateshown lin'Figure 14.

Figure `16 is an elevational view-ofthe abutment plate shown inFigure l5, asf-viewed fromv'rightvtoleft.-

Figure 17 is a plan view of the push rod as-ftheicombined abutment and clevis plate is beingthreadedthereon.

Figure V18 isa plan view ofanlassernbly` -showingon an enlarged scale the screw take- -up ',devicelin assembled relation'with the operating lever.

Figure 19 is a plan view showing ,the 'operating v:lever arm inassembled relationion thesaddlef-bracket.'1.

Figure 20 is axlongitudinalfelevational.y -viewfofvthe assembly shown in Figurel 19.- 'I

Figure 2l is a vertical end viewfof the structure shown in Figure20 as viewed from -righttouleftw Figure 22 is a plan view of the--pawl thrust v member showingthe same on an Venlargedscale. f-

Figure 23 is a verticalfend viewrof. the'fth-rustf-member shown in Figure 22 Figure 24 is a longitudinal elevationalnview on larged scale of the screw-take up ,devicew Figure 25 is a vertical transverse sectional vv iew ltaken through the screw take up device and ona line 25--25 of Figure24 v ln said drawings 10-10 'indicates the eentersill members of the car' and secured theretois aV bracketfll` for supporting the airbrake cylinder 12, the latter being bolted or otherwise securedto the bracket as indicated at 13. The cylinder 12 is provided with the usual push rod 14 which is pivotally connected at 15Qto the brake leverage system as indicated bythe live lever A16, center rod 17 and dead lever 18.`

The dead lever-184s pivotally ymountedat 19 on a bracket 20 whichn tur-n is securedto theenter -sill at 21 and the respective 'deadand live levers are pivotally united at an intermediate location by pintles22. Pivotally connected to the outer! ends of' the respective live and dead levers are top rods 24 which in Iturn lead to the truck (not shown). The live and dead levers are supported from ,the 'center sill Vby means `of lever guides indicated at 25. v

The center connection' 17 includes tWo `enddsections indicated at '26 and'27 .and the adjacentl ends of said sections are screw-threaded tolpresent right and-v left screw-threaded ends as. shown at'28 and 29lrespectively. The screw-threade'd' ends 28 and 29 are connectedby a screw-threaded take-up device 30 which-includes a complementary screw-threaded turnbuckle 31 having tubular extensions 32' and 33 for supporting the rods at an appreciable distance from the screw-threaded portions of the turnbuckle. The'extension 33 'is providedwith a pair of flanges 34-,34 located inspaced `relation on member 33 and welded theretoat 35.

A ratchet wheel member 36 is iixedly secured Ato the turnbuckle by welding as indicated at r3'/ and disposed at an appreciable'distancefrom the'anges 34.

Rotation of the take-up device 30in-a take-up direction is effected through the medium of a bell crank lever having an operating arm 38 onwhich a pawl arm 39 is pivotally mounted for up and down movement. The lever arm 38 is mounted to have' swinging movement in a plane at right angles to'the axisof rotationof the take up device vand vto this end is pivotally mounted onia trunnion 40 integrally formed on a'saddle member 41.?- The saddle member 41 is in the form ofv an'inver-t'ed Unand includes a concave shaped seat 42 corresponding in=shape to the circular-shaped tubular extensionf33` and `-the said U shape is extended'rto providedepending"walls 43-43.

allA CII- The saddle member 41 straddles the tubular member 33 with the concave seat seating on the circular shaped surface of the said member 33 and the walls 43-43 extend beyond the latter and are apertured to receive a cotter pin 44 whereby the saddle member is maintained in position against the take up member. The saddle member is disposed between the spaced flanges 34-34 and is thereby retained in axial alignment on the take up device.

The lever 38 is maintained in position on the trunnion 40 by a washer 45 which is secured in place against the face of the trunnion by a headed rivet 46 which extends through the trunnion and washer and is formed with a countersunk head 47. The lever is further sup ported on each side of its pivotal axis by means of webs 48-48 which lie at each side of the trunnion 40 and form an underlying support for the lever to prevent undue play between the parts. The lever 38 extends downwardly at an angle to pass beneath the cylinder and connect with spring mechanism as will hereinafter be described.

The pawl arm 39 is preferably formed of a circularly shaped bar which is bent to L shape to form angularly related arms indicated at 49 and 50 respectively. the former being disposed to sweep across the face of the ratchet wheel 36 and the latter is pivotally mounted in hollow tubular bearings 51-51 disposed at the side of the lever arm 38 and welded thereto at 52.

Intermediate the bearings 51-51, there is disposed a thrust member 53 which encircles the arm 50 of the pawl arm and is riveted thereto at 54. At the lower portion of the thrust member 53 there is welded at 5S a jawlike piece 56 having upper and lower faces as indicated at 56a and 56h and arranged and adapted to respectively contact the upper and lower faces of the arm 38 to limit rocking movement of the pawl arm.

The teeth of the ratchet wheel member 36 are of such a form as to present on one side a concave shaped pocket 57 and on the opposite side a convex shape contour 58 with a tangentially related slope 59 connecting the convex shape with the concave pocket of the next adjacent tooth. This arrangement of concave and convex surfaces in combination with a gentle connecting incline permits the arm 39 to ride above the teeth and independently thereof when the bell crank lever is swung in unison with the forward movement of the push rod and engaging the teeth when returned by the spring mechanism.

The outer end of the arm 38 which is slotted at 61 is extended outwardly towards the cylinder and beneath the same tn connect with operating spring mechanism 62 which is disposed below the level of the push rod and between the latter and the center sill.

The spring mechanism 62 is supported at one end by a bracket 63 which is rigidly mounted on the cylinder at 64 and at the opposite end by a bracket plate 65 rigidly secured to the center sill and which extends outwardly and downwardly therefrom to support the opposite end of the spring mechanism.

The spring mechanism 62 includes a slide 66 consisting of a pair of rail members 67-67 which extends through a guide bracket 68 and adiacent the opposite end the slide is formed with a shoulder 69. interposed between the shoulder 69 and the guide bracket 68 is a coil spring 70 which encircles the rails. Projecting beyond the shoulder 69 is a pair of jaws as indicated at 7l and 72 between which the outer end of the downwardly extggding lever 38 is received and pivotally connected at a.

The rail members are maintained in spaced relation by a hollow tubular member 73 and a toothed block 74, said respective members being welded to the rails as indicated at 75 and 76 respectively. The member 73 is `extended to project beyond the shoulder 69 and is welded thereto at 77 and to the upper jaw piece 72. The toothed.

block 74 which includes three teeth 78, 79 and 80 is disposed in proximity to the guide bracket 68.

Extending within the tubular section 73 is a supporting rod 81 which is formed with a vertically extending stem` Vportion 82 which tits into the bracket 63 and is supported thereby. The guide bracket 66 includes a pair of side walls 83-83 and upper and lower walls S4 and 85 which combine to form an open ended box-shaped member to allow the rail portion of the slide to move freely therein.

The side walls 83-83 are extended downwardly to form lugs 86-86 between which a weighted pawl 87 is pivotally mounted, said pawl having a detent portion 88 arranged to successively engage with the teeth 78, 79 and 80 of the toothed block to hold the spring compression at various stages of piston travel.

The slide 66 being slidably mounted in the guide bracket 68 and the supporting rod 81 having sliding contact within the tubular center member 73 provides a telescopic effect which allows for self-adjustment in length between the stationary guide bracket 68 and the bracket 63 on the cylinder and thus allows for variations in the length of the push rod.

Compression movement of the spring is etfected through the medium of an abutment 89 carried by the push rod 14 and said abutment extends downwardly to engage with the shoulder 69 of the spring mechanism. The abutment member 89 is in the form of an angle shaped bracket having in addition to the abutment wall 89 a horizontally disposed wall 90 arranged to overlie the upper surface of the upper jaw piece 9i of the push rod. The wall 90 is notched to present a concave shaped contour 92 conforming in shape to the outer contour 93 of a clevis 94 and the meeting edges of said walls 90 and the outer contour 93 of the clevis are welded together at 95 to form an integral structure. The abutment wall 89 is apertured at 96 for the accommodation of the stem 97 of the push rod 14, and the said aperture 96 is formed of slightly elongated shape by depressing a portion of the body of the plate as indicated at 98.

The formation of the abutment wall 89 in an integral structure with the clevis 94 thus provides a rigid onepiece structure supported by the stem of the push rod and by the pintle at avlocation above and below the jaws of the push rod; The fact that the aperture 96 is of elongated shape enables the threading of the abutment and clevis assembly at such an angle as to clear the jawed portion of the push rod, as best shown by reference to Figure 17.

The spring 70 is maintained under initial compression between the shoulder 69 and the guide bracket 63 by means of stops 99 which engage with the side walls 83-83 of the guide bracket. The spring mechanism assembly 62 may thus be applied in place as a unit with the shoulder 69 of the spring contacting the abutment wall 89 of the push rod, the telescoping character of the supporting bracket 81 allowing for variations in the length of the push rod.

The operation of the mechanism is as follows: Assuming the brake parts and slack adjuster mechanism to be in released position as shown in Figures l, 3 and 7, the push rod moves forwardly upon the application of braking pressure taking along shoulder 69 of the spring mechanism by reason of the co-acting engagement between said shoulder and the abutment 89 of the push rod. The forward movement of the push rod is accompanied by a swinging movement of arm 38 as shown by Aconventional dot and dash lines indicated at 100 in Figure 18. Compression of the spring is held at various intervals of push rod travel by reason of the coacting engagement between detent 8S of the pawl 87 and teeth 7S, 79 and 80 as shown in Figure 8.

Upon the push rod travel exceeding the required predetermined extent of travel the teeth override the pawl as shown in Figur 9 and the spring then returns to release position and swings the lever 38 on its pivot with the arm 39 engaging the seat 57 and thereby rotating the take-up device in a take-up direction, the pawl 87 meanwhile being moved to an overbalanced non-operative position by the returning slide 66 as shown in Figure l0. Upon complete release of the brake and spring mechanism the weighted pawl 87 returns to normal vertical release position and in readiness for the next braking operation.

I claim:

l. In a slack adjuster mechanism for the brake system of a car structure, said brake including a brake applying cylinder and a push rod actuated thereby, brake levers interconnected by a tie rod connection, one of said levers being pivotally mounted on the car structure and the other lever pivoted to the push rod, said tie rod connection including a screwthreaded section and a complementary screwthreaded rotary take up member cooperating therewith whereby the length of the connection is varied by rotation of the take up member in a take up direction to shorten the rod and thereby take up slack in the system; a ratchet wheel secured to the take up member, a bell crank lever having angularly related arms and pivotally mounted on the take up member and having an arm adapted and arranged to have intermittent ratcheting engagement with the ratchet wheel upon swinging movement of the lever about its pivotal axis and having the other arm extending towards the push rod and beneath the brake cylinder; and a spring mechanism acting upon the last named lever arm for moving the same in a take up direction, said spring being energized by movement of the push rod in a brake applying direction and upon release of energy operating to effect movement of the related bell crank arm in a direction to take up slack, said spring mechanism having relatively stationary supporting members carried by the brake cylinder and car structure respectively and including a floating shouldered slide member telescopically related to said respective supporting members and having the spring encircling the slide member and disposed between the shoulder of the oating member and the supporting member on the car structure; and an abutment carried by the push rod arranged and adapted to engage with the shoulder of the slide member to energize the spring upon movement of the push rod in a brake applying direction.

2. In a slack adjuster mechanism for the brake system of a car structure including a live lever, a brake applying cylinder and a push rod actuated thereby, said push rod including an elongated stem portion with a jaw portion including a pair of jaws at the outer end straddling the live lever, a clevis straddling the jaws of the push rod and a pintle extending through the clevis jaws and live lever, a rotary take up member in the brake system for varying the relation between the brake parts by rotation of the device in a take up direction, a spring mechanism acting upon the rotary member for moving the take up device in a take up direction, said spring mechanism being energized by movement of the push rod and including a shoulder acted upon by the push rod when moved in a brake applying direction; the herein described improvement including an abutment member carried by the push rod, said abutment member being of angle shape and having one wall resting on the jaw portion at the end of the push rod and welded to the clevis and having the adjacent wall encircling the stem of the push rod and extending downwardly to engage with the shoulder of the spring mechanism.

3. In a slack adjuster mechanism for the brake of a car structure including a live lever, a brake applying cylinder and a push rod actuated thereby, said push rod including an elongated stem portion and a pair of j aws straddling the live lever and a clevis straddling the jaws o f the push rod and a pintle extending through the clevis jaws and live lever, a tie rod connection pivotally connected to the live lever at an appreciable distance from the push rod, said tie rod connection including a screw-threaded section and a screw-threaded rotary take up member cooperating therewith whereby the length of the connection is Varied by rotation of the device in a take up direction, a ratchet secured to the take up, a bell crank lever pivoted on the take up device and having an arm adapted and arranged to have intermittent ratcheting engagement with the ratchet and having the other arm extending towards the push rod and beneath the brake cylinder, and a spring mechanism acting upon the last named arm for moving the same in a take up direction, said spring being energized by movement of the push rod in a brake applying direction, the herein described improvement which includes spring mechanism having relatively stationary supporting members carried by the cylinder and car structure respectively and a floating shouldered slide member telescopically related to said respective stationary members; a spring encircling the slide and disposed between the shoulder of the oating member and the stationary member mounted on the car structure; and an abutment ca rried by the push rod arranged and adapted to engage with the shoulder of the spring mechanism, said abutment member being of angle shape and having one wall resting on the jaw end of the push rod and welded to the clevis and having the adjacent wall encircling the stem of .the push rod and extending downwardly to engage with the shoulder of the spring mechanism.

References Cited in the le of this patent UNITED STATES PATENTS Number Name Date 2,646,137 Dorey July 2l, 1953 2,646,138 Dorey July 2l, 1953 2,646,139 Dorey July 21, 1953 2,646,140 Dorey July 21, 1953 2,646,141 Dorey July 2l, 1953

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